In which a Love Triangle results in the two suitors, who had previously been competing over the same person, developing romantic feelings for each other instead. Might happen in a Harem Genre romance, if two of the leftover suitors end up together.
At least one character in the love triangle needs to be gay or bisexual for this to work. For that reason, it's most commonly seen in works with lots of LGBT characters, such as Fanfiction, New Media, and the yaoi/yuri genre.
- In Long Long Man, Chi, who is dating Tooru, spends most of the series dealing with her conflicting feelings for Long, who seems to be interested in her. You probably figured this out just by what page you're on, but the twist in the final commercial is that Long only ever had eyes for Tooru.
- In Cardcaptor Sakura, one of the initial sources of Syaoran's rivalry toward Sakura is that they both have crushes on Yukito. Once Syaoran realizes that he's more attracted to Yukito's moon-based magic than Yukito himself, he starts crushing on Sakura instead, and they end the series as the Official Couple.
- The Twist Ending of an arc of School Mermaid. Two girls go into the school at the same time to try to use the mermaid flesh to make the same boy fall for them. When dawn falls the only mermaid they killed has the wrong name, forcing both of them to cast the spell on each other instead. They instantly transform from hated enemies into a lovey-dovey couple.
- Implied in My Teen Romantic Comedy SNAFU, in which both Yui Yuigahama and Yukino Yukinoshita are (secretly) in love with Hachiman Hikigaya, but the former has a close friendship with Yukino... too close for many of their close ones, at the point Hachiman once mistaken (with a purpose) her last name for "Yurigahama."
- In ×××HOLiC, Doumeki and Kohane are two of the many people interested in Watanuki. They're shown to be married after a Time Skip, although it's implied that they got together not out of love, but to have children who could continue Doumeki's family legacy and protect the now-immortal Watanuki.
- Slightly subverted in Gankona, Unnachgiebig, Unità. Although Germany and Japan fought over Italy and both ended up together, it was only after Italy chose them both. Them getting together completed the polyamorous relationship with all three paired with each other.
- Light and Dark The Adventures of Dark Yagami: Desk Lady and the girl from the bus are both interested in Dark, but then have sex with each other. Subverted when the girl from the bus ends up with Dark in the end.
- Inverted in My Immortal: Vampire and Draco used to be a couple, but broke up and are now both in love with Ebony.
- In the Harry Potter fanfic The Red Knight, it's revealed that Violet Potter (fem!Harry) used to date Ron, who also had an affair with Hermione. After he betrayed them, leading to their deaths, they went back in time and became a lesbian couple.
- The premise of Plan B: Bruno plans to steal back his ex-girlfriend Laura by seducing her bisexual new boyfriend Pablo. He intends for his seduction to be faked, but it doesn't end that way.
- When in Rome: Beth ends up with an Unwanted Harem as a result of a love spell gone wrong. After the spell is broken, two of her suitors are last seen flirting during Beth's wedding.
- At the start of Carry On, Simon is dating Agatha and has a passionate hatred of his roommate/nemesis Baz who has his eye on Agatha too. However, it turns out that Simon's passionate hatred of Baz is actually passionate Belligerent Sexual Tension and Baz has really been in love with Simon all along and only pretended to be interested in Agatha to push Simon's buttons.
- In The Love Interest, Caden and Dylan are two teens groomed from birth by a secret organization to become the perfect love interest for a girl destined to become famous some day. They're expected to compete for the girl's affections in a classic "Nice Guy vs. Bad Boy" battle with the loser being killed off, but they fall in love with each other instead and choose to defy the organization so that they can be together.
- The Merry Wives of Windsor ends with (among other things) Miss Anne Page giving her two parentally-approved but comically inept suitors the slip and running away with a much more charming (and younger) man. The 21st-century remake The Very Merry Wives of Windsor, Iowa, set just after Iowa's legalization of gay marriage, has young Miss Anne Page coming out as straight and marrying a young man...leaving behind her two (still older, and not quite as inept) lesbian suitors, who seem quite happy with each other.
- Gay love triangle version in Boy Meets Boy: Skids loves Mikhael, Tybalt tries to seduce Mikhael, and eventually Skids and Tybalt end up together.
- Attempted in Friendly Hostility: After his much-older girlfriend dumps him, Paolo hits on her ex-husband, Leslie, but Leslie turns him down, saying Paolo is just confused about what he wants.
- Homestuck has Dave and Karkat both competing for the attention of Terezi, with the subtext between them mostly Played for Laughs. After John's Cosmic Retcon, however, neither seem particularly interested in getting with Terezi and instead spend most of the story's later arcs growing closer to each other. By the end, they are very heavily implied to have become an item.
- In Korean yuri webcomic It'd Be Great If You Didn't Exist, the protagonist Guk-Hwa finds out her boyfriend is cheating on her, and dumps him, only to end up in a romance with the other woman.
- Ménage à 3:
- While "romantic" is a bit of a stretch, after Yuki and Sonya's disastrous competition for Gary's affection and after they also served as rivals for Zii, the two of them realize that they have more fun with their rivalry and have a long period where they just keep egging each other on for hate-sex.
- Also used as a quick gag later on. Two opposite-sex coworkers compete over who can take Peggy to bed, which ends when Peggy declares that she wants a threesome. Unfortunately, the second they get into bed the coworkers realize that they loved each other all along and promptly forget about the frustrated Peggy.
- Scientists found a rare left-coiling snail they named Jeremy. Because its shell coiled counterclockwise, the opposite direction of typical snails, its sex organs could not align with others. Two other left-coiling snails were found but they proceeded to mate with each other instead of Jeremy.
- Somewhat blurring the lines between this and Live-Action TV, two contestants from the Australian version of The Bachelor fell in love.