— Terry McGinnis, on the opposite end of a beating, Batman Beyond
What you do for a living is typically a big part of who you are, and when you start getting serious with a boyfriend or girlfriend, you probably like to talk about how your day went. But what if you spend your day saving the planet from alien invasions? Or hunting down vampire serial killers? What if what you do for a living is so fantastical telling them about your Secret Identity will convince them you are a liar (in which case they dump you), convince them you are insane (in which case they try to have you committed and/or dump you), or horrify them to the point where they (guess what) dump you? Of course, the people you work for in this fantastical world may insist that should you ever tell your significant other, you'd have to immediately kill them.
Is it any surprise, then, that the Masquerade will (make you) kill your dating life?
A lot of times, the pool of eligible bachelor(ette)s in on the Masquerade is rather small, and since Everybody Has Lots of Sex, it won't take long for you to work your way through them. But if you try to date outside of the masquerade, be prepared to stonewall every time your new beau asks "So how was your day?" or "When do I get to meet your friends at work?" or "Why do you always come home with blood-stained clothes and smelling of gunpowder?" Expect much angst about having to lie to the current most important person in your life that doesn't have a spot in the opening credits. That's if you can keep the many, many lies from collapsing in on themselves, that is. These relationships tend to end in one of two ways (don't they all?), with several subtypes:
The strain is too much, and you break up.
A. Your Love Interest senses you're hiding something, and threatens to call it off if you don't come clean. You can't, so they do. Or maybe you try to come clean and either they don't believe you, or the proof you provide freaks them out.
B. You can't stand lying all the time, and call things off yourself.
Lelouch Lamperouge of Code Geass suffered several problems with his love interests—particularly Shirley—because of his masquerade as Zero to which her death can be directly attributed.
Intially with Suzaku and Euphemia, but having their respective masquerades broken allowed them both to genuinely get to know each other. But Euphemia didn't tell Suzaku about Lelouch being her brother and still trusted him, which got her killed.
This is a common theme of Codename: Sailor V, in which Minako's love life is forever ruined by her duty. In the very first issue, she crushes on a boy who suggests she wear a red ribbon in her hair (said ribbon being an iconic accessory of the character). He turns out to be an agent of the Dark Kingdom and she is forced to kill him. Throughout the series, various one-shot crushes come in and out of her life, forever chased off in some fashion by the consequences of her job. Finally, she seems to be getting somewhere when her Mysterious Protector, Kaitou Ace, finally gets close to her...only to be revealed to also be Danburite, the Big Bad of the series. Upon her killing him, he leaves her with an (accurate) prediction that she will never find love because she will always put her duty first.
Something like this happened to one of the handlers in Gunslinger Girl. His girlfriend even pointed out about how he always smell like gunpowder despite supposedly working for "a social welfare agency".
A literal version occurs with cyborg girl Rico, who finds herself attracted to a boy she meets while doing her recon. When she runs into the boy during the hit, the brainwashed girl obeys her handler's instructions and shoots him dead.
In Wei▀ Kreuz, Ken Hidaka's entire love life can be summed up this way. He breaks up with his first girlfriend, Yuriko, because he simply can't handle lying to her and can't see any other way to keep her safe, then does it again when the first one doesn't quite take; the second, Reiko, turns out to be one of his targets, so that doesn't end at all well either. Unsurprisingly, by Gluhen he seems to have given up dating entirely.
To clarify: Stargirl knew that Billy was 16, and that Billy was Captain Marvel, and that it was still Billy's basic personality when he was in Captain Marvel mode. But the rest of the Justice Society, mostly made up of elder statesmen of the superhero crowd, did not know about Captain Marvel's secret teenaged identity, which made the relationship look highly improper. Jay Garrick, the Flash, flatly told Captain Marvel to break it off, and he did so rather than reveal his identity to the older members of the team.
Bruce Wayne, of all people, admits this to Vicki Vale when he realizes this is why she's deduced his secret identity, thus why Ra's al Ghul wants her dead.
Tim Drake (3rd Robin) has a fondness of dating civilians (Arianna, Zoanne, Tam) compared to the other Robins. These relationships always end up going south, unsurprisingly. With Arianna and Zoanne, they have no clue of his secret identity, and with Tam, she managed to keep his secret AND dodge all death threats at her for being associated with him fairly well, but broke up anyways. Even with his longest relationship, Stephanie Brown (Spoiler), they were dating as superheroes and not civilians because he couldn't give away his real identity. They had problems due to Robin's secretiveness and only patched things up when Batman forcefully revealed Robin's real name to her.
In the MAD parody of the Adam West Batman series, Robin does a Face-Heel Turn because he's upset with being a victim of this trope time and again.
In True Lies Schwarzenegger's character, a secret agent, pretends to his wife that he is an exceptionally dull computer salesman. This nearly kills his marriage.
In Batman Forever Bruce Wayne hides the fact that he's Batman from Dr. Chase Meridian...even as she demands to see Batman. She gets her wish, and Bruce still almost would've kept his Masquerade in force...until Two-Face and The Riddler kidnap her.
In Men In Black there's a third type: inductees are to sever all ties with their old life - including loved ones. One scene shows Agent Kay pining over a lost love (and is later reunited with her, but only after he leaves MIB and has his memory wiped).
Come the sequel, she's left him, in a pseudo-Type 1a situation.
Played for laughs in Mr. and Mrs. Smith. Both are Elite Spies of different (and competing) agencies who both live an elaborate lie (similar to Schwarzenegger's in True Lies. It all goes south when they are on the same job. Classical Type 3 situation...
A large element of the "indie short film" Eagles Are Turning People Into Horses. In fact, the point is for the "broken masquerade" to scare his girlfriend away.
In Point of No Return (an American remake of La Femme Nikita), the lead is incredibly happy with her newfound boyfriend but can't take all the lying on top of being forced to kill people. Since she can't just drop out of the secret agency that recruited her, she runs away.
The Masquerade killed Harry Dresden's dating life: the only girlfriend he's ever had (as an adult, that is) got herself turned into a half-vampire while attempting to interview a bunch of vampires out for Harry's head. And eventually, Harry was forced to kill her in Changes.
Or the time a demon interrupted one of their dates.
Wizards live longer than muggles. Some of the more venerable wizards know their great-great-great-great-grandkids, and sometimes further.
Elaine, his teenage girlfriend. Harry killed their adoptive father Justin DuMorne in self defense, and Elaine disappeared in the property damage. Note - they were both adopted, so there shouldn't be any Squick involved in their relationship.
Karrin Murphy, a vanilla mortal, has deep feelings for Harry and he has them back, but as she knows he can live for centuries and she will only live for one at most, she and he never get together, not even casually because Harry wouldn't do things by halves. At the end of Changes they try to go for it but a set back occurs. Then in Cold Days Murphy all but says she does love Harry and will be with him, even if he walks into hell.
The Scarlet Pimpernel: Percy Blakeney had his marriage (nearly) killed by The Masquerade. He probably would have told his wife the truth had he not been led to believe she was a sympathizer for the other side just a few hours after the wedding. The lies and miscommunications that followed drive the plot of the book.
Comes up in the all three books of Marie Brennan's Onyx Court series.
In the first book, Lune and Deven fall in love while Lune is posing as a mortal to uncover secrets in Queen Elizabeth's court. Lune spends much time angsting about how he can never know what she truly is. Initially ends in a type 1B, but becomes a type 2B once Deven gets into terrible trouble trying to find her again.
In the second book, Antony refuses to tell his wife, Kate, about the Onyx Court, and she calls him on keeping secrets more than once. Unusually, nothing ends up changing. Kate just eventually accepts that there are certain things that her husband just can't/won't tell her.
The third book also plays with this trope: while The Masquerade has clearly not limited Galen's dating life, society dictates that he must marry outside it. Galen agonizes for months about whether and how to tell his fiancee, Delphia. Subverted when he does decide to tell her and her reaction, after a brief initial shock, is pretty much, "Faeries living under London? Cool!"
The stress of the masquerade getting in the way is part of the reason Thrix is the Christmas Cake in Lonely Werewolf Girl (the other part of the reason is she is a chronic workaholic). In the sequel her only love interest turned out to be a case of Dating Catwoman.
Spike and Cindy from the Thursday Next series are a subversion as they're happy together and Spike manages to fail to understand when Cindy subtly tells him.
Referenced in The Laundry Series. People in the Laundry are both legally and magically compelled not to speak of their work with anyone not cleared to know about magic and the occult, so Bob reflects on the difficulties this situation creates for one's social life when you're not permitted to explain a single thing about one's work. Bob and others in the Laundry are basically forced to only date within the agency, which for Bob meant a very restricted dating pool of one delusional narcissist his age until Mo joined up. Everyone is almost entirely cut off from their families for the same reasons - all Bob's parents know is that he's a civil servant.
Discussed in How To Be A Superhero as an inevitable side effect of having a Secret Keeper; no matter how well-meaning your significant other is, she's not going to understand superheroic issues like cleaning alien hell-slime off your costume.
In Beautiful Creatures, the Caster community keeps to itself. This makes dating nearly impossible for Lena, once she starts becoming interested in the mortal Ethan.
This trope's pretty much in full force in Dexter. Invoked quite literally in the 4th season finale when the serial killer Dexter was trying to kill murdered Dexter's wife
This happens in Teen Wolf. A Type Three for Scott and Allison. Scott loved to whine and moan about it and pass his masquerade duties on to someone else (mainly Stiles) so that he could try to avert the trope.
This happens in The Vampire Diaries with Stefan and Elena. This is because Stefan kept his identity as a vampire a secret from Elena.
This happens in Torchwood too. When Gwen's boyfriend finds out, however, their relationship improves considerably after a bit of awkwardness with the rest of the team.
Ianto: Well, this is unprecedented, the fiance finding out.
Tosh: Mainly because we're all sad and single.
On Warehouse 13, Pete's love interest fled the town after being possessed by an artifact that caused her to try and kill him. Thankfully, she stopped him before he used up his one chance to tell someone the truth about his job.
Happens all the time in Charmed. Most of the main characters end up married to men who were already part of the masquerade to avoid this.
Buffy's social life was constantly being derailed by this. An early boyfriend, Owen, followed her one night, and nearly got killed by a vampire, without ever realizing that's what happened to him, but he got off on the excitement and wanted to do it again, so she dumped him. Scott dumped her because she seemed "distant." Then with Riley in season 4, it turns out that they are both in on the masquerade, and have been hiding it from each other, until they run into each other in the middle of a fight. They get over it after learning about each other though. Something similar happens with Principal Wood in season 7 but he knew who she was, all along. Xander and Willow's major love interests were part of the masquerade or, in Oz's case, introduced.
On Angel Wesley's girlfriend was introduced as the daughter of a client; the father intended to use her as a Virgin Sacrifice. She eventually breaks up with Wes after he gets shot, as she realizes how dangerous his job is. Cordelia went on dates a lot in the first season, but stopped when the work became more time-consuming. Her threemainlove interests were all part of the masquerade, as were the major love interests of the rest of the main characters.
A staple of Hannah Montana. It's particularly amusing when Miley's date is somewhere in the vicinity of a Hannah event and she chooses (poorly) to attend both engagements simultaneously.
Chloe, whose whole relationship with Jimmy, from beginning to end, was strained by her keeping first Clark's secrets and later, Davis'.
Starts with Sydney's fiancee in the pilot of Alias and goes downhill from there. After the Time Skip between seasons 2 and 3, she barely interacts with anyone who's not in on the conspiracy or a target of her mission.
In Chuck, Chuck's few attempts to date someone who wasn't Sarah ended up going sour pretty much for this reason.
One episode revealed the case where he was on the other side of the equation. His college girlfriend was actually recruited into Fulcrum probably even before they started dating. After he was expelled, her handler forced her to end the relationship. When they meet again, they're on opposite sides (he's CIA/NSA, she's Fulcrum).
In The Sarah Jane Adventures, Sarah Jane gets a package containing an alien being while getting a visit from her boyfriend. Fortunately, Clyde and Rani are there to cover for her.
In Stargate SG-1: Samantha Carter has difficulty forming lasting romantic relationships for many reasons, including the fact that she secretly travels the galaxy and fights aliens for a living. (Being somewhat Married to the Job and having feelings for her commanding officer probably also have something to do with it, not to mention the fact that we don't call her "Black Widow Carter" for nothing.) The first time she manages to have a stable relationship with anyone outside the masquerade (romantic or not) is with her boyfriend Pete. He finds himself a little put out by her constant secrecy, but being a cop, decides to do some digging rather than forcing a confrontation. He ends up stumbling into the crossfire of a fight with a Goa'uld and getting shot, which leads Sam to give him the whole story while he's in the hospital. He actually accepts it extremely well, but their relationship eventually fails for other reasons.
One of their interactions does bring about this great bit of dialogue:
Pete: I realize this must be weird for you, worrying about place settings when we can be destroyed by aliens at any minute.
Sam: A little.
Pete: ... We're not about to be destroyed by aliens, are we?
Of course, they are right about to be destroyed by aliens, them and the rest of the galaxy.
Parodied in Saturday Night Live where Danny Devito played a mobster who kept telling his wife that he can't tell her what he does for a living. Not only does she clearly know, but she's advising him on what to wear not to be seen, which gun to use for his hit and where to dump the body.
Just ask Cally Stone of Dark Oracle about this one. Every potential relationship she has (and most of her friendships) get torpedoed by her attempts at dealing with the comic book that has taken over her life. Conversely, her brother Lance, and his best friend Dizzy, probably wouldn't have dating lives if the comic had forced them together with their respective girlfriends.
George from ''Being Human" deals with this twice: with Sam, his rebound girlfriend, whom he nearly transforms in front of because she won't let him get out of going to a parent-teacher conference for her daughter on the night of a full moon; and, most notably, with Nina, who starts out quite angry and annoyed about being constantly left out of the loop when it comes to George's secrets and then gets introduced to the masquerade when George accidently scratches her partway through a transformation and turns her into a werewolf. Her inability to cope with her introduction to the masquerade leads them to break up for a while.
H2O: Just Add Water zigs and zags around on this trope with the four different mermaids (and one secret keeper) over the seasons:
Cleo and Lewis's troubles have little to do with the masquerade, and are more mundane in nature. He's a little too involved in helping that it makes him a poor boyfriend.
Emma's boyfriends become pushy over the secret and Emma pushes them away over it (or it causes a huge fight). She only reveals her secret to her second love interest in the last episode.
Rikki starts out with the problem of being a mermaid in love with a guy (Zane) whose made it his only mission to prove Mermaids exist. Later he feels that mermaid stuff is coming before him in in their relationship. Incidentally Rikki's closeness to her mermaid sisters is strained when she lets Zane know she is, but doesn't tell them, and forbids him from telling them he knows. So we have a Masquerade in a Masquerade. Bella's initial problems with Will are much along these lines, as he's sure weird stuff is going on and wants the truth (which Rikki, Cleo, Bella, and Lewis don't want him to know).
In Power Rangers Zeo Tommy tries to go out on a date with someone outside the masquerade only to be called away by preparations for the next monster attack. Later he actually gets to the date, only to be called away by an actual monster attack.
Suits has obvious attraction between Mike and Rachel, but Mike realizes he can't continue the relationship while hiding the fact he doesn't have a law degree. Harvey orders Mike to end the relationship, and he reluctantly obeys.
In Reaper, Andi finds out Sam's secret (him working for The Devil) and stays with Sam.
One of Reluctant Sidekick Mark's biggest issues with Ace Lightning is losing girlfriends who think he's an insensitive jerk whenever he stands them up to go help Ace save the world. Two series on one of them is still bitter.
Later, at the end of the second season, after collapsing from a gambit by one of Nick's enemies that caused Juliet to forget all about Nick, and only him, she eventually regains her memories and learns about the whole affair by pressuring his Wesen friends to be honest with her. When she sees Bud, Rosalie, and Monroe change, she leaves the spice shop only to return a minute later and reveals she will learn to handle it and wants them to tell her everything.
The entire 'subplot' mechanic in Spycraft is this trope, with about half the standard subplots being about the difficulties caused in your personal life by your spy antics and the other half being about your personal life popping up and messing up missions. It's a lot more entertaining than it sounds.
Similarly, the "story hooks" in superhero game Truth & Justice are designed to enable this. Your Qualities (skills and traits) are also your health, so taking damage decreases them - and the first Quality you assign damage to in a fight is your vote for where your plot goes next. Mind that you can have relationships as Qualities. This lead to the joke that you could punch Spider-Man in the Girlfriend and that's why there was always trouble with Mary Jane.
Averted in the Persona 3 and Persona 4 games from the Shin Megami Tensei franchise. Later into the games, you will actually find your life much much easier if you date/socialize/karaoke/have coffee on a regular basis and cram only for the exams. The dates in Persona 3 are even designed such that you are only required to max out your Knowledge stat by the last quarter of the game.
It's more like an inversion - being in SEES or the Investigation Team is the protagonist's "in" with several girls considered highly desirable by the rest of the school.
This trope is why so many superheroes from the Global Guardians PBEM Universe are divorced (in some cases, divorced multiple times). It also explains why so many of them are "girl/guy in every port" types.
In Spinnerette, on top of the usual schedule priority issues, Heather has to wear a fat suit to hide her extra arms.
Terry McGinnis of Batman Beyond: His steady girlfriend Dana got really sick of being perpetually Stood Up, and his foray into other prospects got him into a Dating Catwoman mess. Luckily for him, Dana eventually comes around, as seen in the Distant Finale the show got in Justice League. She knows his secret identity by then, so at some point she either figured it out or Terry wised up and just told her.
In Sym-Bionic Titan, Kimmy is fed up with Octus (with Lance and Illana) "going to the bathroom" all the time, especially when he leaves right before the prom.
Jem and Jerrica Benton are the same person. Unfortunately, Jerrica's boyfriend Rio doesn't know this, and he falls in love with Jem. If she only told Rio the truth everything wouldn't be so complicated and she wouldn't have to be her own boyfriend's mistress.
In W.I.T.C.H., when Matt and Will started dating, he got more than a little suspicious of why she kept running off. Once he found out the reason why, he was more supportive... though, it didn't stop him from wanting to help. By the end of the second season, they evolved into a Battle Couple.
Peter from The Spectacular Spider-Man is a Type 1 with Liz. He had to keep missing dates with her to fight crime, and he eventually broke up with her so she'd be free to seek out someone else.
Men In Black: The Animated Series has a pre-MiB girlfriend run into J while he and K are on stakeout. After they kiss a bit, K (who was distracted) neuralizes the girl and tells her to go home.
More like the Masquerade Will Ruin Your Friendship, but the same general concept applies to Peter's and Harry's friendship in Ultimate Spider-Man. Peter's inability to tell Harry the truth along with the constant ditching puts a considerable strain on their friendship.
In his autobiography, Have a Nice Day!, Mick Foley recounts having a conversation with a woman he was dating shortly before he was to lose a Loser Leaves Town match in his independent days. Mick tries his best to uphold Kayfabe, dancing around the fact that he would have to leave her, when the girl revealed that A) she already knew wrestling was fake, and B) she'd deduced he was going to lose, and leave town, because he'd already packed his things in his car.
Such is the life of intelligence agents and certain special forces. However in the case of the CIA, at least, agents are permitted one contact on the "outside" to know who they really work for in the event something unfortunate does happen.
Indeed, CIA agents are generally permitted to tell whoever it is they're in a long-term relationship with at the time, as well as certain other people if the circumstances require it. This is a lot easier (for most agents, at least) than you might think; being a CIA agent isn't usually so much about having a fake identity and running around chasing people as it is a lot of making contacts and so on while using your own name and lying about your job to everyone on the outside. As far as your parents (for instance) or any short-term flings you might have are concerned, you probably work for the Department of State or Defense or Agriculture, or perhaps even a private company.
This is what happened to Carlos Hathcock. Only in his case, he was already married when his wife found out that he was a Marine sniper. Naturally, she freaked out and left him.