In Gantz, this is subverted with Kurono and Kishimoto. When Kishimoto died during a mission, Kurono thought to try and pursue her original that was still living a normal life. However, she ends up thinking Kurono is a nutty stalker and runs away from him.
However, this trope is followed in relation to Kato and Kishimoto. It's implied that Kato has finally decided to get together with Kishimoto's original, and she seems to have taken a liking to him.
And the manga does this to a T with Reika's very own Kurono, who she resurrects with this trope in mind.
In Threads Of Time, this is what happens to Moon-Bin at the end. Although he isn't able to end up with Atan Hadas from the past, when he goes back into present time, it's implied that he ends up with a girl (that always liked him) who is identical to Atan Hadas.
In Cross Game, the characters meet Akane who happens to look exactly like Wakaba, Kou's dead love interest and the Tsukushima family's daughter. Subverted in that Kou and Akane don't end up together, and the main characters theorize (somewhat bizarrely) that Akane was sent by Wakaba to let them know that it's okay to move on. Yeah, whatever lets you sleep at night, bub.
Subverted in the Black Cat anime, where, for an episode, Train meets a girl who is physically identical to Saya. The thing is, he never really shows much romantic interest towards her, and ends up leaving and forgetting about her. Which certainly contributes to the idea of his character — that he loved Saya's carefree way of life, not that he romantically loved her. Therefore, since the girl had a completely different way of life and occupation, he certainly wouldn't be all that interested in her.
Trigun is an excellent, if subtle, example. The Technical Pacifist protagonist Vash the Stampede refuses to kill anyone because of the teachings of his mother-figure— even though his brother killed her and some (millions of) colonists on their arrival on the world over one hundred years ago and both villains and protagonists point out how unreasonable he is on the Sliding Scaleof Idealism Versus Cynicism. The catch is that one of the two insurance girls following him throughout the series (similarly an idealist and Vash's love interest) in an act of If You Kill Him, You Will Be Just Like Him is superimposed with the image of said dead mother figure. Of course, she looks exactly the same, just with much, much, shorter hair (for fans who are half-blind).
Toyed with a bit, and subverted in Full Metal Panic! during The Second Raid. Sousuke is separated from Kaname by Mithril, and goes into his huge Heroic BSOD. He ends up meeting a Chinese prostitute who looks exactly like Kaname, and decides to hire her to chat with him. The subversion comes in that, as soon as she starts making advances on him and attempts to kiss him, he completely freaks out and runs away.
Fist of the North Star played around this trope when Mamiya was first introduced, whose resemblance to Yuria (Kenshiro's supposedly dead fiancee) was the first thing he noticed about her. Subverted in that even though Mamiya is in love with Kenshiro at first, his feelings are not mutual. Also, Yuria is later revealed to be Not Quite Dead yet.
Non-romantic example, in the 2003 anime version of Fullmetal Alchemist after Ed is trapped in our world on the other side of the gate, he befriends a boy named Alfons who is this world's counterpart to his brother Alphonse in his world.
Also, probably, a non-romantic one. He befriends Noah, who is probably Rose's counterpart.
Another one from the Bleach movie, Memories of Nobody: After Senna sacrifices herself, Ichigo sees a girl who looks and sounds just like her run past on the bridge.
InuYashaplays with this trope in the situation between Inuyasha, Kikyo, and Kagome. After Kikyo's death, plenty of characters who knew Kikyo are struck by the similarity between Kikyo and Kagome (justified by the fact that Kagome is Kikyo's reincarnation), resulting in Kagome angsting over being compared to Kikyo. Inuyasha himself was initially repulsed by Kagome because her scent was so similar to Kikyo, something he got over when he realised their scents weren't the same. He didn't actually notice the physical resemblence between the two until he caught Kagome sleeping one time and had the chance to really study her face to see what everyone else was going on about; for him it didn't really factor in to how he handled Kagome. As a result, the trope is played with because while the resemblence is there, it's not the driving force behind their relationship or the reason Inuyasha became attracted to Kagome. The differences between Kagome and Kikyo are, in fact, so stark, that Kikyo and Kagome have trouble understanding each other and Inuyasha never has any trouble keeping the two women straight in his head because their personalities and motivations are very different.
Toyed with in MÄR with Koyuki being Ginta's love interest from the real world, and he ends up having fallen for Snow, her exact counterpart in the fantasy world. In the end, he decides to return to the real world and, in the anime, starts dating Koyuki, who Snow's spirit has joined with.
In Fushigi Yuugi, Hotohori marries Houki, a woman from his harem that looks just like a female version of Nuriko. Also, Houki herself had once been in a relationship with a man that looked just like Hotohori later revealed to be his long-lost older brother
Ultimately averted in Project ARMS. Almost immediately after the apparent death of Katsumi, a girl named Kei is introduced. She looks exactly like Katsumi (to the point where it's later revealed that she was Katsumi's clone and Ryo is obvious struck by this resemblance. But then Ryo and Kei only ever are friends, while Hayato becomes her love interest. Katsumi, meanwhile, turns out to be alive, and Ryo spends the series trying to rescue her.
In Mahou Sensei Negima! Eva from the future states that one of her goals is to find an "extra Nagi", after she gets a dimension jumping machine from Chao.
In Nanatsu No Taizai, Meliodas originally had a lover named Elizabeth nicknamed Liz in his past. In the present, a princess who exactly looks like his dead lover except for hairstyle and color is in love with him. Not only does she uncannily look like his dead lover, but she is also named Elizabeth, and also seems to have ties with his past.
In the X-Men comics, after Jean Grey "died" in The Dark Phoenix Saga, her boyfriend, Scott Summers, met and married Maddie Pryor, a girl who looked just like her. Of course, it's not a straight example because 1) Maddie turned out to be a clone of Jean created by an enemy, and 2) Jean wasn't really dead and later came back to marry Scott. The original script would've had Maddie be someone who looked like Jean. That's it. No reincarnation, no clone, just someone who happens to look like her. Unfortunately, an anniversary was rolling around, and Marvel wanted something big. So, they retconned Maddie into a clone for the sake of a story.
In The Incal, John Difool meets, falls in love and loses a beautiful "Aristro" (she goes off with another guy.) Later he meets Animah, who exactly resembles her. (Strangely, given the metaphysical manipulation that occur in reference to John, this seems to have happened by accident.
In Countdown to Final Crisis The Atom Ray Palmer ended up in a parallel universe where his counterpart had just died. He tried to make a new life for himself there and got together with the counterpart of his insane ex-wife Jean Loring. Amazingly enough, things were actually going pretty well — but since this is Countdown, which was described on this wiki as DC's love letter to Kill 'em All, it didn't last.
In RASL, the protagonist's girlfriend is killed and then he finds himself in a parallel universe where she's still alive — and so is his longer-dead wife. This being RASL, this only makes his troubles more complicated.
In Runaways, Xavin once impersonated Nico, knowing that Karolina had a crush on her and thinking that this might make their betrothal easier. It backfired pretty badly, creeping Karolina out and making her even more aware of the differences between her and Xavin.
Which is even more ridiculous when you remember that "Vampire" is supposed to be Harry and he doesn't look like Draco.
The Monsters UniversityAlternate Universe fanfic A Sinister Mind (part of a series of AU stories written by Crazybird101) reveals that Johnny Worthington had a childhood friend named Marcus, who eventually became his lover. He was a lizard with crimson scales, red eyes, and four fronds. Marcus is forced to leave his abusive aunt and move to a different home, and Johnny doesn't see him for years. When the events of the movie come around, Johnny meets Randy Boggs, who looks almost like Marcus.
Marcus of course doesn't die; he shows up in another fanfic called A growing bond. He is the main villain in A fighting bond, but in Silent obsession, it is revealed he had died in childbirth.
In Susie Q, Zach falls for Susie, a ghost who needs to settle her family's unresolved affairs before moving on to the afterlife. With the help of Zach, she succeeds and moves on to the afterlife and is reunited with grandfather and boyfriend. The next day at school, Zach runs into a new student named Maggie (played by the same actress). It's strongly implied that she's Susie's reincarnation, sans Susie's memories. The situation prompts Zack to give a baffled glance to the camera
Xanadu has the protagonist parting with a muse played by Olivia Newton John, only to meet an identical waitress at the end. Or the waitress actually is said muse, trying for a version of the relationship her family can at least pretend they don't know about. Some of her parents' remarks leave it a bit ambiguous.
A Connecticut Yankee In King Arthur's Court (1949). Bing Crosby's character meets and falls in love with Alisande La Carteloise ("Sandy") in King Arthur's time. When he returns to the present, he meets a woman who looks just like her.
Likewise, Black Knight has Martin Lawrence meeting a modern ringer for the love interest he left behind in the past. Nicky also has a scar on her neck at the exact same spot where Percival held a sword to Victoria's throat.
The same thing basically happens in A Kid in King Arthur's Court, though the girl actually seems to recognize him there, so who knows what's up with that. It's implied that this was Merlin's doing. The novelization of the film plays the trope straight, with his teammate being merely a lookalike with the same name.
Done in Bedazzled (2000), even though his dream girl is actually a normal person who was already taken, he still ends up with a woman who looks exactly like her except brunette, while the dream girl was a blonde. Made all the more interesting because the whole plot is based around his wish to be with his dream girl, especially after finding out that she just broke up with her boyfriend. His final wish (for her to live a happy life) results in the break-up never happening.
Some onscreen adaptions of The Nutcracker end like this, with toymaker's nephew looking exactly like the eponymous prince (Note, in the original story they are actually the same person.)
In The Forbidden Kingdom, the protagonist's love interest dies in her attempt to assassinate the villain, but in the ending, he meets an identical girl in the present.
Meet Joe Black seriously inverts this trope. At the very beginning of the movie, Death takes on the aspect of a man who gets hit by a truck just after the female lead falls madly in love with him. Death then proceeds to fall in love with her, and at the end of the movie when he must leave to get back to work, he resurrects the real Love Interest to take his place.
At the end of Night at the Museum — Battle of the Smithsonian, where Larry happens to meet a young woman who looks exactly like Amelia Earhart, and also has a poor sense of direction.
In the film The One, Jet Li fights his Evil Twin from an alternate dimension. Evil Jet kills Good Jet's wife, frames him, and tries to kill him to become a god. After much chop-sockey, good Jet Li ends up in a version of Los Angeles where the original copy of him has long since been killed off and meets a version of his former wife exactly as he did in his world.
This was the plan by Jason Statham's character, who knew that sending him back to his own universe would result in him being put away for his wife's murder.
Sort of used in Dark City — Emma Murdoch gets all her memories erased and she becomes Anna, and John Murdoch decides to start over with her. Justified, since their relationship beforehand was fake—Emma's memories of the marriage were no more real than Anna's past, and John had already lost his fake memories. So this replacement relationship is more real than the original one.
Subverted at the end of Date With An Angel; Jim is stunned when he meets a nurse who is a dead ringer for the angel he's been caring for the entire movie — and then she reveals that she is the angel, she's now on indefinite leave to be with him and has left her wings at home. (And has traded in her bird call speech for inexplicably French-accented English.)
She was played by French actress Emmanuelle Beart. Mystery solved.
Even more interesting because the Time Travel part is heavily implied to have been All Just a Dream, and yet Nicky has a scar exactly where The Dragon cut Victoria (Vicky) with his sword in the past.
Given a dark twist in Vertigo. Scottie, despondent over the death of Madeleine, finds a woman named Judy who looks almost exactly like her. The two begin dating, but Scottie starts pressuring Judy to dress exactly like Madeleine. However, what he doesn't know is that Judy actually IS Madeleine, who faked her death but now is struck with a terrible case of Loves My Alter Ego.
In BeerFest during a series of events Landfill is killed, he is eventually replaced by his brother who happens to look exactly like him (he even asks to be called Landfill in honor of his departed brother) and his widow ends up marrying him and subsequently forgets about the original.
She replaces Landfill's photo on her nightstand with his twin's... as the twin is doing her from behind.
In the 1984 film of A Christmas Carol (1984), the man Belle ended up marrying after leaving Scrooge looks just like his past self, possibly played by the same actor.
Bicentennial Man involves Andrew, a Ridiculously Human Robot played by Robin Williams, watch the family that owns him grow. When the owner's young daughter has grown, she subtly reveals that she has feelings for Andrew. Having only begun his journey to understand what it means to be human, Andrew has no idea what she means and suggests that she marry her fiancé. She does so. Years later, he is freed by his owner and leaves to find others like him. In the process, he meets an inventor who changes Andrew's appearance to that of a human (his organs are still artificial). He comes back to his former owner's home and kisses the woman he assumes to be the daughter. She freaks out, and it's revealed that many years have passed, and the woman he kissed is her grown-up granddaughter (played by the same actress). And yes, they end up together.
Technically, so is Jack 49, as both are clones of Julia's dead husband.
In Captain America (1990), Steve's love interest from the 1940s waited 15 years after he disappeared to marry and have a daughter (played by the same actress). Steve and the daughter are a couple by the end of the film.
In Andrew M. Greeley's Angel Fire, Sean Desmond meets an Irish woman who is a dead ringer for Gabriella, the angel who has shepherded him through the entire book, after she leaves for good. It's implied that Gabriella knew of this coming meeting and used the woman's appearance in order to prime Sean for a relationship with her.
In Heir Apparent, the protagonist is trapped in a virtual reality game and ends up developing a bit of a crush on one of the characters. For obvious reasons, they can't exactly be together once she's escaped the game. Luckily he looks just like the game's Teen Genius creator, who shows up to apologize to the heroine personally and seems flattered that she liked the character based on him...
In Stephenie Meyer's The Host, one human has his girlfriend taken over by a Soul. The free humans then remove the Soul, but the girlfriend is brain-dead due to the possession by this point—so they just stick the Soul back in the body. The original mind's boyfriend then stays with the Soul-in-the-body, despite said Soul being the reason that his girlfriend died at all.
In the Last Herald-Mage trilogy of the Heralds of Valdemar series, The Hero Vanyel loses his first Love Interest, Tylendel, in a truly epic tragedy that starts him on the path to becoming the most powerful Herald-Mage in the history of the kingdom. Seventeen years later, he finds a new love interest, Stefan, who is physically dissimilar, but still bears an uncanny psychic resemblance to Tylendel, up to and including forming a lifebond with Van. It turns out that 'Lendel was reincarnated as Stefan, though most of the main characters are ignorant of this until close to the end of the story.
John Perry from Old Man's War is very upset by his wife's death. Near the end of the book he meets a special forces soldier who has a body cloned from his his wife's DNA, who looks exactly like her. They end up together.
The Redwall novel Martin the Warrior has an odd case of this. In the end, it's revealed that the traveler narrating the story is a dead ringer for Rose, Martin's love interest who was killed by the Big Bad in the final battle. The catch? The two will never meet, as Martin lived and died many generations before the traveler told the story. Slightly better than most examples in that the two characters are, you know, mice.
Inverted in Solaris—a doppelganger is created to remind the protagonist of a love interest he failed to save, and he eventually falls in love with her. This is not a case of Replacement Goldfish, as he remains well aware that the copy isn't the same person as the original. It still ends rather badly, though.
Harry Harrison's Starworld (the third in the To the Stars trilogy) has the protagonist sent to Israel to meet a contact, and he at first is shocked to see Sarah, his dead love who was killed in the first book. Subverted in that he then starts to see differences and, after talking to her, finds out that she's Sarah's sister. They end up having sex, but it turns out they're both married (he got married in book two) and have no intention of leaving their spouses.
In both the novel and subsequent TV movie Tek War, Jake Cardigan falls in love with an android built in the image of Beth Kittridge. The android dies in a Heroic Sacrifice. Then Jake meets the real Beth.
In The Vampire Diaries, Stefan initially fell for Elena because she looked just like his long-dead love interest, Katherine.
In the final book of The Dark Tower, Susannah Dean travels to an alternate New York City where she meets an alternate version of her (deceased) husband Eddie, their young (also deceased) friend Jake, and even an Earth-dog version of their (guess) billy-bumbler Oy.
Live Action TV
In episode 4 season 3 of Charmed, "All Halliwell's Eve" The sisters meet a nice guy in the past, who helps them out a lot. When they travel back to the present (several hundred years later) Prue meets an exact look alike (also played by the same actor) in P3.
Subverted in "Second Soul". One man's wife dies and donates her body to an alien race (they can occupy and revive recently dead bodies, and need to do so to live). He meets the recipient, and finds out that they do sometimes inherit random memories from their hosts, but she does not fall in love with him, becomes bothered by him following her around and eventually gets a restraining order against him. It's even hinted that the process is set up to prevent the aliens from being close to family members of their hosts, presumably to prevent this from becoming a regular occurrence.
"If I look like her, if I sound like her, I might be her? The answer is no."
In "In Another Life", a man mourning the death of his wife gets sent to a parallel universe. He quickly tries to find the alternate version of her, only to discover she already has a boyfriend. In the end, when he decides to stay, he meets the alternate version of his wife again and they strike up a friendship, leaving him hopeful that they may get together in the future.
Avoided in Chou Ninja Tai Inazuma Spark, the samurai from the Edo period lost his sister in an alien attack, then at the end of the story goes to live in the future, where he finds out that someone who looks just like his sister is an actress. At first he's elated to be "reunited" with his dead sister but goes running off screaming when he finds out that she's The Ditz.
Happens to Adam in Mighty Morphin' Power Rangers. The Rangers are sent back in time, he meets a girl, then meets a girl who looks exactly like her when the Rangers are returned to the present.
And in Power Rangers Time Force, Jen was initially engaged to Alex, but after he is (supposedly) killed by Ransik, she time travels to the past and meets Wes, who looks exactly like Alex. Though at first hostile towards him, Jen begins warming up to and ultimately finds her Second Love with Wes.
In The 4400, Richard was in love with and planning to marry a woman named Lilly when he was abducted in 1953. he was later returned in 2003, and his lover had died many years before. However, he met and later married a fellow returnee who had been abducted in the 90s who was identical to his beloved. Her name? Lilly. She was the grandaughter of the woman he had been involved with. As they grow closer he admits that at first he was drawn to her because of the resemblance but later it was all about her.
Jackie Tyler became a widow while her daughter was a baby. In a parallel universe, Pete Tyler lost his wife during the Cybermen incident. When the former ended up in the universe of the latter, the two paired up, meaning that each was the other's Doppelgänger Replacement Love Interest.
As pictured, Rose gets her own Doppelgänger Replacement Love Interest in the form of a half human clone of the Doctor who looks exactly like him and has all his memories, but who ages like a human and is willing to stay with her in the parallel world.
Invoked in "The Caretaker" - the Twelfth Doctor assumes that Clara's new boyfriend is the Adorkable floppy-haired history teacher who wears a bow tie and can't talk without gesturing heavily with his hands. He gives her his blessing while thinking this. When he discovers that her boyfriend is actually a charismatic former soldier who looks and acts absolutely nothing like he ever did - and Clara claims that the other man is not her type - he is not pleased.
A variation was overused to the point of boredom on the original Fantasy Island, when Rourke reveals that a visitor's fantasy love interest just happens to be another visitor to the island.
Daytime soaps do this a lot. Most of the time it's not supernatural, just a way to bring back an actor who has been killed off, such as when Angie Hubbard of All My Children and The City met and married a man who looked exactly like her late husband Jesse. An example of the supernatural sort was on General Hospital when Anna's alien friend Casey had to return to his home planet, and then Anna met a lookalike human, Shep Casey.
Used in Wonder Woman when the series moved from WW2 to the (then) present day. WW's long-time Love Interest Steve Trevor had been established as an Army officer in the 1940s, so in order to have "him" around in The Seventies, he had to be replaced by his identically-named son — both played by the same actor, of course.
Averted in the pilot episode of Time Trax, where Darien's Love Interest in his own time is killed by the Big Bad. He goes back to the 20th century, chasing the escaped criminals only to encounter her Identical Grandmother. Nother happens between them, although she helps him in a later episode.
In Fringe, "our" Lincoln Lee and "their" Olivia Dunham become this for each other.
In one episode of Friends, we meet Russ, Rachel's latest boyfriend who has the same face, voice and mannerisms as Ross but has a slightly different haircut.
This comes up again in some of the Mirror Universe stories of Star Trek: Deep Space Nine. Sisko meets the counterpart of his dead wife, Jennifer, and Kira meets the counterpart to her dead lover, Vedek Bareil.
A rather weird example occurred in Farscape. At one point, John Crichton gets split in two, with the implication that they are both "real." Soon after, the crew gets separated into two groups, each with one Crichton. Aeryn, who'd been growing closer to Crichton during the course of the series, finally consummates her relationship with the Crichton she's with. He eventually performs a Heroic Sacrifice, and the remaining Crichton finds it an uphill battle to win back her love.
Happens in Eureka when Henry and some others travel to 1947 and back, arriving at an alternate present. Henry finds his Alternate Universe self is married to a girl he barely knows. He tries to play the part of husband, but she confronts him and he spills the beans. She's married to a guy who doesn't know her. They get better.
This is, essentially, what starts the plot of The Vampire Diaries: Stefan returns to Mystic Falls after finding out about the existance of Elena Gilbert, a human girl who looks exactly like his deceased ex Katherine Pierce (later explained to be because they're descendants, since Elena was adopted, and both are Doppelgangers). However, he subverts this slightly in that he falls in love with her because she's the opposite of Katherine.
There's a perfect example of this trope in How I Met Your Mother, when it's revealed that Scooter, Lily's high school boyfriend who all series long has had a crush on Lily, ultimately goes on to marry Stripper Lily, her doppelgänger from "Double Date" and "46 minutes".
A variation in the Stargate SG-1 episode "Ripple Effect." Among the dozen other SG-1s from alternate realities who show up on the base, one of them has Martouf, a Tok'ra who developed quite an interest in Samantha Carter. Though they don't hook up in the episode, it does provide some nice closure for Sam (and the fans) since the regular-universe Martouf was killed before the relationship had a chance to develop.
Zoey 101 has Zoey moving to England and Chase becoming friends with a blonde girl who resembles Zoey in appearance, but personality-wise, she is rude and repulsive. The rest of the characters know Chase is hanging out with her for this reason, but Chase was in denial.
This often happens with laterally reincarnated innerwalkers in Feng Shui.
Deconstructed in Silent Hill 2, where James can choose to be with Maria, who is an idealized doppelganger of his dead wife Mary. In the ending Maria starts to cough, implying that James is doomed to relive the pain of her dying from a terminal illness just like his wife did. The game implies that this is what James just deserves for clinging to an image of his wife instead of moving on. Or, in another interpretation, refusing to accept responsibility for what he did, and failing to understand why what he did was wrong and selfish.
In the game version of Da Capo this happens in the Miharu route. Girl gets hit by car, girl gets replaced by robotic duplicate. Boy loves robot. Robot malfunctions. Girl comes back. Boy gets together with girl...
The NES game Astyanax ends with the hero back in his normal highschool world, but the new student is a dead ringer for the fairy companion who pulled a heroic sacrifice.. but the game never says whether perhaps she was just reborn or what.
At the end of Sam & Max: Freelance Police: The Devil's Playhouse, Max is Killed Off for Real. The cutscene shows the devastated Sam leaving all his friends and walking aimlessly through the town. Suddenly, he sees the Time Travel elevator from Season Two and finds there Max from an Alternate Timeline, in which Sam is the one who died. After an awkward moment, they decide to resume their mischief and pretend none of this happened.
By Poker Night 2, they remember the events with laughter, possibly blocking out the memory of losing their best friend.
In .hack//G.U., after Haseo loses Shino to Triedge, he meets Atoli who happens to have the near exact same avatar design, save a color change. However, while her looks are similar, her personality is very different from Shino's, which causes Haseo to (initially) hate her.
In Winter Shard, if Frederone's love interest Rosetta dies, Zewoe creates a clone of her to please him. This enrages Federone, either because he promised Rosetta that he wouldn't try to resurrect her or because he did resurrect her only for her to be Driven to Suicide because of her religious beliefs, and he actually orders Marliene to wear a mask at all times when around him because he doesn't want to be reminded of how much she resembles Rosetta. He can either come around to accept Marliene as a legitimate love interest in her own right, or he can reject her.
The alternate Harley Quinn falls for the main universe's Joker, as her Joker had been killed, but eventually dumps him and moves on when she realizes what an asshole he is.
The evil alternate Superman declares he will kill the main universe's Superman and take his Lois Lane. When Superman points out she would be disgusted and terrified of him, evil Superman says he doesn't care as long as Lois is alive again. Fortunately, Superman defeats the evil one.
In Sluggy Freelance, both Zoe and her Dimension of Lame counterpart are this for Torg. First Torg has a Cannot Spit It Out crush on Zoe, then he gets trapped in the Dimension of Lame and hooks up with that universe's Zoe, then Alt-Zoe is killed by Lord Horribus and Torg returns to his home universe, and starts crushing on Zoe all over again.
And it turns out Torg is this for Alt-Zoe as well, since her dimension's Torg vanished long ago after the two were romantically involved.
Teen Titansmay have done a variant: Beast Boy's love interest, Terra, is turned to stone. Then, in the series finale (several seasons later), he suddenly sees a girl who looks just like her and is convinced she's the real Terra (whose petrified body has vanished), even though she at least claims to not know him or remember anything about being a superhero. They do not wind up getting together in the end, and whether the girl really was Terra or just a lookalike is left ambiguous. Word Of God says she is. It's a throwback to the comics, however the second Terra was a clone and the first really was dead.
ReBoot: After Glitch-Bob's attempt to split apart via portal goes explodey, Dot decides to marry the other Bob. Dot was already leaning towards choosing the other Bob, and Glitch-Bob's accident pushed her the rest of the way. Then it turns out that the other Bob is actually the Big Bad. Whoops.
On Futurama, Fry (and the Professor and Bender) get hurtled into the future so far, they reach the end of the universe and watch a new, identical one come into existence. Fry gets together with the Leela from that universe (after the native Fry is killed by their time-machine's arrival). Uncharacteristically for this trope, though, we actually get to see the original Leela spend the rest of her life miserable and alone.
At the end of The Jetsons Meet the Flintstones, Judy Jetson is pining for her stone-age boyfriend Iggy Sandstone (met during a time-travel mishap), and then meets his identical space-age descendant, who's no less cool. Both boys are into rock music, of course.
In an early episode of The Simpsons Homer becomes the manager for a country singer named Lurleen Lumpkin, who falls in love with him and tries to get him to have an affair with her. Several seasons later, she appears again, and it's revealed that she's been married 5 times since, and all her ex-husbands (and her current boyfriend) look just like Homer.