We all know the classic Love Triangle and all its many configurations. It can be a major source of drama in any situation, but there are times when the love triangle only appears to be there. Maybe one of the corners misinterprets something one of the others said, or someone outside the triangle gets the wrong impression.
A number of situations could lead to this.
Bob and Alice are dating and are good friends with Claire. Bob makes some offhand comment to David about Claire. David repeats it to Emily and through Gossip Evolution Claire hears it and thinks Bob wants to break up with Alice and date her. She, however, has no feelings for Bob and tries to get Bob and Alice to reconcile their non-existent problems.
Or, Bob and Alice are very close friends, Like Brother and Sister. Or even actual brother and sister. Charlie has a crush on Alice, but sees the pair's affection for each other and thinks they are in love. Since Charlie wants Alice to be happy, he does not pursue her.
Or, Diana sees Bob being openly affectionate to Claire when he's dating Alice. She thinks he's cheating on Alice and tells Elaine who tells Frank who tells Georgia who tells Harriet. Claire may end up being Bob's cousin or just a good friend.
One defining quality of this trope is that Bob and/or Alice are usually completely oblivious to what everyone else thinks is happening.
Imaginary love triangles that come to be seen as real by one or more of the corners blur the line between imagined and real. They can then be represented in the diagrams in Triang Relations, either alongside the real triangle or as the real triangle. The second example above, for instance, is the "forbidden love triangle" a → b ↔ c when "a" fails to act. The All Love Is Unrequited triangles a → b → c and a → b → c → a are also useful both as imaginary triangles and as real triangles to superimpose imaginary triangles on.
- Fairy Tail has a love triangle existing only in the mind of Juvia, who misinterpreted something Gray said to think he loved Lucy, and thus believes her to be a rival in love. Ironically, Gray and Lucy are just friends and Gray doesn't seem to have an interest in love, let alone notice Juvia's affections for him. The imaginary rivalry settles down after a while, but that doesn't stop Juvia from sometimes flaunting her "progress with Gray-sama" in front of Lucy. Later it's taken Up to Eleven and now she believes that she's in a Love Dodecahedron.
- In ...Virgin Love, Chiharu's knowledge of Kaoru's sex life starts to make Daigo think there might have been something between them and Chiharu decides to fan the flames. Kaoru later reveals to Daigo that Chiharu is his cousin and he's just being had.
- Dangan Ronpa 3: During an episode of Side:Despair, It seems that there is one, with Chisa thinking that she is competing with Juzo Sakakura for the heart of their mutual friend Munakata, but Juzo states that it's an idiotic idea. Then it turns out that this is subverted, and she was Right for the Wrong Reasons, Juzo is indeed in love with Munakata, but afraid of his reaction and seeing as Munakata is in love with Chisa, he decides to back down, so he was never competing in the first place.
- Gamers! has a setup where all the characters involved think they're in a Love Dodecahedron, but it's really just a love triangle with an Official Couple on the side. Aguri loves Tasuku who loves her back. Karen loves Keita who reciprocates. Chiaki and Keita are made for each other but their relationship is a little complicated. This is muddied however with people's perceptions. Keita and Aguri think that Tasuku is two-timing Aguri with Chiaki and/or Karen. Karen at points thinks that Keita is in love with Chiaki. Chiaki initially thinks Keita is being led on by Aguri until he asks Karen out and thus "escapes" her. And Tasuku is deliberately setting up Keita's love triangle, at least in part because he thinks that Aguri's two-timing him. The imaginary triangles and dodecahedrons are complicated from the start, and the constant misunderstandings mean it just goes downhill from there.
- Mint na Bokura has Chris, who falls for Noel and goes to great lengths in order to steal "her" away from her "boyfriend" (who in reality is the Secret Keeper for Noel's true gender).
- Pokémon: Several one-off characters who develop crushes on Ash aren't happy to see Misty, May, or Dawn travelling with him.
- Miette invokes this, pretending to have a romantic interest in Ash, all just to see Serena get jealous. Serena doesn't buy it, for the most part.
- Episode 5 of Persona 4: The Animation centers around on of these, though parts of it are real. Ai Ebihara likes Kou, who likes Chie. The immaginary dodecahedron is created when Ai gets Yu Narukami to pretend to be her boyfriend, and then everyone starts thinking Chie likes Yu...
- In Magi: The Labyrinth of Magic, as she began to develop feelings for Solomon, Sheba became jealous of Solomon's close friend Arba, seeing her as the ultimate rival. But in reality, the relationship between Solomon and Arba were only familial and once Arba realized Sheba would be a good match for Solomon, she approached Sheba and gave her the blessing to be Solomon's wife.
- Samurai Flamenco has a very odd example where Goto is "dating" a girl who is literally imaginary. He spurn Mari's advances because of her. The girlfriend is jealous of Masayoshi at one point, implying that Goto has feelings for him, but feels guilty about straying from his girlfriend. But she isn't actually an obstacle to either of these relationships. it's that kind of a show
- Takeo from My Love Story!! initially believes his crush Yamato likes his Bishōnen best friend Suna, since girls usually flock around Suna while Takeo is ignored due to being a bit of a Gonk. Takeo is very wrong - Yamato only has eyes for him. Suna is the one who arranges to clear up the misunderstanding and get them together.
- In the elementary chapters of Wandering Son, Saori develops a crush on Nitori but becomes very jealous of Nitori's friendship with Takatsuki. The two are frequently Mistaken for Romance and are very close. This causes a drift in Saori's and Takatsuki's friendship. None of this is helped by the fact Nitori is confused about whether she likes Takatsuki platonically or romantically. She confesses to Takatsuki but is turned down, only for later that day for Saori to confess to her. When Nitori declines Saori's affections and mentions that she confessed to Takatsuki, this causes Saori to fall into a depression and her friendship with both to be ruined for several years. By high school the drama had died down, with all three being friends (especially Takatsuki and Chiba). It helps that Saori and Nitori both have a boyfriend and a girlfriend respectively.
- Naruto Gaiden has a variation on this as the one believing the love triangle is the child of two of the members involved. Sarada is Sasuke's and Sakura's daughter. Her father has been gone her entire life and she knows little of him. One day she spots a picture of Sasuke and Karin, which causes her to start doubting her parentage. She finds more evidence of Karin being her mother as time goes on. It turns out she is Sakura's biological daughter. Karin gave up on Sasuke years ago. Karin and Sakura are even actually friendly as adults.
- Akatsuki no Yona had a Love Triangle played completely straight in its beginning chapters, but it slowly morphed into this as the series went on. When they were growing up together, Yona had always loved Su-Won, while Hak had always loved Yona. After Su-Won murdered Yona's father and usurped her throne while she escaped with Hak, Yona naturally fell out of love with him. Much later, she's fallen for Hak, but he believes her still keeping the hairpin Su-Won had given her is a symbol that she still loves him.
- In Chapter 74 of Kaguya-sama: Love Is War, Kaguya, Shirogane, and Ishigami all imagine that they're in a love triangle due to the three of them having binge-read too much Shoujo manga.
- Chapter 86 of Horimiya takes this Up to Eleven with an imaginary harem forming around Sakura in the eyes of two background characters. Said "harem" includes Hori.
- In a classic issue, a guy named Jeff who previously hit on Linda -aka, the titular heroine-, thought she was cheating on him with a professor. However, Linda is not interested in either of them.
- In Krypton Returns, H'el sees Supergirl hugging Superboy and gets jealous thinking she's falling for Superboy. However Kara loved neither of them.
- Wonder Woman once laughed when a fellow Justice Leaguer mentioned the idea of Diana being romantically involved with Superman. Her heart, at the time, lay elsewhere.
- Advice and Trust: Ritsuko loves Gendo and believes that Rei is a threat to her "relationship" with him. In reality, Rei is not in love with Gendo (but rather with Shinji and Asuka) or romantically drawn to him, and Gendo regards Rei as his daughter... and Ritsuko as an useful pawn.
- Evangelion 303: Subverted. Saburo thinks that he is in a Love Triangle with Kaworu and Rei, since Kaworu spends a long time watching over Rei when she's in a coma and later they often go out together. However, Kaworu sees Rei like a friend, and their "dates" are mostly two friends hanging together. Ironically, Saburo's actions - breaking up with Kaworu out of jealousy and later stalking him - push Kaworu towards Rei.
- Higher Learning: Shinji and Asuka love each other. However, after half-hearing - and severely misunderstanding - a conversation between Asuka and their teacher Kaoru, he thinks the older man has seduced Asuka. He spends several days depressed and on the verge of a nervous breakdown until he finally confronts Asuka and learns that nothing has happened between her and Kaoru.
- In Marks of Time, Lyla and her husband each suspect that the other has found a new lover.
- Superwomen of Eva 2: Lone Heir of Krypton: Misato and Kaji are dating. At the same time, Shinji is in love with Asuka and completely oblivious to her loving him back. Misato misunderstands Shinji when he remarks that he is in love with a girl and wrongly thinks Shinji has fallen for her. She spends several chapters trying to let him down gently every time he asks for relationship advice to win Asuka over. Misato's reaction when she finally finds out the truth is priceless.
- This happens twice in All This Sh*t is Twice as Weird, both times with the same characters. Most of the cast can see what's actually going on; but since Cullen and Victoria are Twice Shy and she's Like Brother and Sister with two other men, it's an easy mistake to make. He gets better, though not before Dorian takes the chance to troll him over it.
- In Hop To It, Marinette spends several chapters treating Jack as a rival for Adrien's affections, though Jack is completely oblivious to this. They only find out what was going on after Jack happens to mention her boyfriend Diego to Alya, who panics and scrambles to call off the cruel prank Marinette had set up.
- Two of these are found in the first piece of the Dragon Age: Inquisition High School A.U. series Skyhold Academy Yearbook. In both cases, two-thirds of the triangles are unaware that the third person thinks there is a triangle at all.
- This trope is a very common evolution of the Miraculous Love Square. Marinette/Ladybug and Adrien/Cat Noir will have revealed their true identities to each other, and will be publically dating/married in their civilian identities. Then they're caught making out while one of them is transformed by someone who does not know their secret identities. Hilarity Ensues.
- Star Wars:
- The Luke/Leia/Han Love Triangle is probably the Trope Codifier, at least by the time Return of the Jedi rolls around. Once we find out Luke and Leia are siblings, their branch disappears, though Han doesn't know that until the end of the movie.
- Played for drama in the Matt Stover novelization of Revenge of the Sith (and to a lesser extent in the movie as well). Anakin thinks that Obi-Wan is his competition for Padme after Obi-Wan visits Padme's residence once early in the morning without his knowledge. This eventually culminates in Anakin Force Choking Padme out of crazed jealousy... although by this time he's already committed wholesale child murder, so this is almost a step down for him.
- The trope is a Batman Gambit by Frank Castle in film the 2004 adaptation of The Punisher, where he makes a mob boss think his wife is having an affair with his (secretly gay) Number Two.
- In Harry Potter, people keep assuming that Harry and his platonic friend Hermione are dating. First, Rita Skeeter's tabloids invent their relationship, leading to issues with her current boyfriend, Krum; Harry finds it rather surreal that a professional Quidditch player four years older than him considers him to be an actual "threat". In the next book, Harry mentions Hermione on his date with Cho; she gets the wrong idea and storms off. Finally, in the last book, his other best friend Ron, who's clearly in love with Hermione, is manipulated by Slytherin's locket, part of which involves trying to convince him that Hermione (and his family) loves Harry more than him.
- In Brat Farrar by Josephine Tey, the protagonist's love interest has a romantically-inclined kid sister who tells him that she's going to marry somebody else — who turns out to be just an old friend, and already married.
- Invoked and yet averted in Northanger Abbey. When Catherine sees her new acquaintance Henry out and about with a young woman, the narrative notes that if this were a different sort of story, she would immediately assume that's his sweetheart and be completely devastated. But because Catherine is smarter than that, she's able to correctly deduce that the young woman is Eleanor, Henry's sister, whom he'd mentioned to her previously.
- Chandler, in both the season 5 and 6 finales, thinks Monica is going to leave him for her ex-boyfriend Richard. Both times Monica has no intention of doing anything of the sort; the first time, she feels nothing for Richard. The second time, she's faced with two proposals, and she not only accepts Chandler's instead of Richard's, but she even proposes to Chandler herself.
- Chandler falls for this again with her so-called soulmate Don and 'the funniest guy she's ever met' Jeffrey. Monica is completely oblivious, as it's based on throwaway comments she can't remember making.
- On Dharma & Greg, Dharma's old friend visits and begins spending a lot of time with her father, Larry. Dharma begins to think she's trying to steal him away from Abbie; in actuality, the friend wanted to spend time with Larry because there was a chance he was her biological father.
- Noah's Arc: Interesting subversion between Alex, Trey and Guy. Alex suspects Trey may be cheating on him with Guy. It turns out Trey is completely innocent, though we learn later that Guy has been secretly pursuing Trey (with Trey being oblivious to this).
- In Gossip Girl, Chuck assumes from spying on Blair that she and Dan have something going on, and so sets them up so that Blair can see Dan doesn't belong in their world. However, Blair is in love with Chuck, and this childishness only leads to her becoming so disgusted with him she actually does go out and find another love interest.
- Deadly Women explores this in many episodes, where the killer will often kill the person she believes to be in love with her boyfriend/husband/stalker victim to Murder the Hypotenuse.
- Buffy the Vampire Slayer:
- In the episode "Triangle," Anya becomes convinced Willow will try to steal Xander away from her. Despite Willow being in a lesbian relationship by this time, she isn't entirely unjustified in her concerns; Willow had already broken up Xander's previous relationship (which is what brought Anya to Sunnydale in the first place), and Willow didn't want her around.
- In Season 2, Angel worries that Xander is a rival, because he can spend his days as well as nights with Buffy. However, while Xander is definitely interested in Buffy, the reverse is not true.
- The Nanny: C.C. is convinced she's in one with Fran for Mr. Sheffield, but the truth is he's completely oblivious to her feelings.
- The Frasier episode "The Rivals" has two imaginary triangles: the usual miscommunication between Frasier and Niles leads to them both believing they're in competition for the same woman, when they're actually seeing two different women. In the end, they freak both women out and end up alone, and they still only figure it out after Frasier proposes a toast to "one pretty remarkable woman" and they say different names.
- On The Musketeers, Rochefort is obsessed with Anne and is convinced that she loves him back. Thus, he believes that he is in a love triangle with both her husband (the king) and the Musketeer Aramis (with whom she had an affair).
- In Iolanthe, the main conflict arises because Phyllis sees her beloved fiancé Strephon kissing a young woman who looks seventeen on account of being a fairy, but is Really 700 Years Old - and his mother.
- In Phoenix Wright: Ace Attorney – Dual Destinies there is a rumor in Themis Legal Academy that Juniper Woods is object of affection of her two best friends, Robin Newman and Hugh O'Conner. Their rivalry in a mock trial is presented as battle over her heart, and rumor claims that Hugh is going to confess his love for her. In reality neither has any romantic feelings for her, what Hugh really wanted to confess is that he's actually much older, and failed his class 7 times in a row while Robin is actually a girl.
- Briefly in Sandra and Woo. Woo thinks his rival, Tibor, is interested in Lily. Turns out she's his daughter.
- Robin of Shortpacked! has a thing for love triangles, and an even bigger thing for Ethan. When she sees Ethan comforting Amber, she immediately thinks she's involved in a love triangle — even though Ethan is gay and not attracted to either of the girls.
- Disney High School:
- An episode of Alvin and the Chipmunks had one involving a Girl of the Week, Simon, and a biker boy. Alvin convinced Simon to try out for a bike competition to impress the girl, only to find out that the biker was her cousin.
- Total Drama, with its numerous Ship Tease moments, provides examples:
- For example, both Trent and Courtney saw themselves in a love triangle when their respective Love Interests, Gwen and Duncan, became friendly during TDA. (Though this may be subverted by the Ass Pulled Retcon in season three claiming that Gwen had always had a crush on Duncan.)
- The inversion may be even more common, when a character is in a love triangle but doesn't notice; Cody's obliviousness to Trent/Gwen in season one would probably be the clearest example (later to be replicated with Cody/Gwen/Duncan in season three).
- An episode of The Simpsons had the family visiting a dude ranch and Lisa falling for a cute boy (voiced by Jonathan Taylor-Thomas). When she runs into a girl who is looking for the boy, Lisa tries to get rid of her. It turns out that girl was the boy's sister, and Lisa's actions make him hate her.
- The Hollow: Kai thinks that there's something going on between Mira and Adam, which he fears since he also starts having feelings for Mira, but it's shown that nothing will come out of Mira and Adam's relationship when she kisses him and he reacts by awkwardly saying he isn't interested.
- On Adventure Time, Finn and Jake both believe that Finn's former Precocious Crush, Princess Bubblegum, has suddenly started to like Finn right when he's become interested in Flame Princess. In reality she was objecting to their relationship for another reason.
- On Young Justice M'gann wants to reconcile with Superboy, but when she asks Nightwing where he is he tells her that he's on a date with their old friend Wendy. Later M'gann finds out that he was basically Playing Cyrano for Wendy's actual new boyfriend, Marvin.
- On Rugrats, Grandpa gets a New Old Flame named Morgana in one episode. It turns out their relationship had ended when she saw him "kissing" another girl; in reality, he had been performing CPR on her as she suffered an asthma attack. That girl eventually became his wife.