Alice and Bob are the two subjects of a rom-com. They've met in a manner most cute, had a few laughs, done an obligatory Falling-in-Love Montage and look all set to book the church/synagogue/registry office/volcano/whatever.
Then, about 60 minutes into the 90-minute movie, there's a sudden wacky misunderstanding where one of them is Mistaken for Cheating. Or Alice realizes her enemies will come after Bob to get to her, and she has to Break His Heart to Save Him. Or The Bet Bob had made that he was using Alice to fulfill is revealed to her. Or maybe they just have a sudden disagreement in their taste of music and both storm off in a huff.
Cue about 20 minutes of moping and trying to move on before they both realise that all they want to do is wait for the other to get out of the bathroom (or maybe join them in there) for the rest of their lives. Depending on the circumstances of the breakup, one person (usually Bob) may need to grovel before he can be forgiven. Then cue the tearful reunion.
- Fushigi Yuugi pulls out one of these every ten episodes. At least. In a 52-episode series.
- Sailor Moon features a second-season break-up when Mamoru has prophetic dreams that compel him to leave Usagi for her own safety. They only get back together in the last few episodes.
- Happens in Back to the Future Part III between Doc Brown and old west schoolteacher Clara Clayton. Notable as its part of a science-fiction comedy movie trilogy that doesn't normally dwell on such things, and that despite the breakup happening over a misunderstanding, no one was really at fault — it's just really hard for someone living in the old west to believe someone who tells them he's a time-traveller from a hundred years in the future.
- Extremely common in sequels where the lead couple had their Relationship Upgrade at the end of the first movie. Bridget Jones: The Edge of Reason is a good example of one where it happens even though the breakup is completely pointless and has no effect on the plot.
- Don Jon:
- Barbara breaks up with Jon halfway through the movie over him lying about his porn addiction.
- Jon also mentions this happening in all romantic movies.
- Bromantic example: in 50/50, protagonist Adam breaks up with best bud/comic relief Kyle because it looks like Kyle is just using Adam's cancer as a chick magnet/ganja pass. Luckily, Adam stumbles upon Kyle's collection of well read books on how to help a loved one with cancer, complete with copious margin notes, and they make up.
- In I Love You, Man the bromance and main storyline feature this. The main character separates from his fiancee for a day or so, but the main Second Act Breakup is between the main character and his new friend.
- In Knocked Up, Allison breaks up with Ben half-way through the movie as she thinks they are not made for another. Needless to say, they reunite at the end.
- Happens in the prime minister David and household staff member Natalie in Love Actually. He saw the American president kissing her on the cheek, thinking Natalie was never interested in him. It wasn't until he saw the Christmas card from her, saying that she was his that he realized that she returned his feelings. Cue him trying to find her house to apologize and her happily accepting it and them making up by kissing at the back of the school's stage. Only for the curtains to rise.
- Subverted in Neighbors; Mac and Kelly have the stereotypical argument where Kelly ends up leaving him with their daughter. The very next scene the two quickly make up.
- Role Models has Paul Rudd's character break up with his girlfriend in Act I, but both of the lead's are "dumped" by their Little Brothers in Act II.
- The X-Files: I Want to Believe has a weirdly low-key example. Scully and Mulder break up, sort of, but they both seem rather unsurprised to find that they can't really stay away from each other for long, and at the end not only is there no groveling, they don't really even apologize and make up — they just quietly go back to acting like it never happened. One gets the impression that they've done this before and while they were both upset, neither of them really thought they were going to stay broken up.
- Tragedy Girls treats Sadie and McKayla's temporary falling-out when the fame begins to go to Sadie's head as a breakup.
- The book of About a Boy subverts this by having Rachel react with amused tolerance when Will reveals that Marcus is not really his son. The movie plays this trope straight while using most of the same lines spoken in a different tone.
- Edward leaves Bella in the second book of the Twilight Saga for her safety and she zombies out for ten pages that are literally blank.
- The Night Huntress books have two; midway through the first book, Bones leaves Cat until she can figure out how she feels about vampires. At the end of the first, leading into the second, Cat writes Bones a Dear John letter.
- In The Valley of Horses, Ayla and Jondolar undergo a temporary break-up when Jondolar finds out about Ayla's past and shows his prejudice against the Clan. In The Mammoth Hunters, Ayla and Jondolar have problems for most of the book which come to a head in the middle when Ayla agrees to meet someone else. If it weren't for the fact that Ayla and Jondolar go through most of The Plains of Passage until they have their fight, making it more of a Third-Act Misunderstanding, the series would have used the exact same plot point three times in a row.
- Taking a leaf out of the Sailor Moon playbook, Roswell ALSO had a contrived, time-travelling break-up in its second season to keep Max and Liz apart. Hooray for romance in the 90s!
- In How I Met Your Mother, Ted and Robin became a couple at the end of Season one. Season two focuses on their relationship and issues that hindered it. Eventually they concluded that because of their differences, they are not meant for each other and in the Season two finale, they revealed to Barney that they broke up.
- Happens in the third act (out of four) of La Bohème because Rodolfo knows he cannot care for his girlfriend, the fatally ill Mimi. He accuses her of cheating on him or wanting to cheat on him, justifying this idea by saying he caught her looking at other men, so they will break up and she will not feel obligated to live with him in squalor and the cold, which is exacerbating her condition. She returns to Rodolfo in the fourth act very close to death.
- The Fenris romance in Dragon Age II has one literally in Act 2, right after Fenris and Hawke consummate the relationship, when he freaks as this causes him to quickly regain and then lose his memories of his life before his scars, leading him to walk out on Hawke. Depending on the player's actions toward Fenris after said incident, it can actually be permanent.
- Ambrosia and Arsenik play along with this trope almost perfectly in War: 13th Day. They're getting along swimmingly until Night blackmails Ambrosia into giving her body to him in exchange for her lover's safety. She agrees but, feeling like it would be cheating, breaks up with Arsenik. Of course, he later finds out and is understandably livid. Like a true gentleman, he decides to defend her honor on the battlefield.
- In Dino Attack RPG, shortly before the mission which led to the discovery of the Dino Island Laboratory, Amanda and Rex broke up. Not due to any misunderstandings or anger between them... but because they both accepted that their relationship couldn't go much farther when they were completely different species. Luckily, this was resolved by the end of the mission, since a freak accident in the lab caused Rex and Dr. Rex to switch bodies, so now Rex and Amanda are both the same species and free to continue their relationship.
- Happens in the Avatar: The Last Airbender episode "The Beach." At the end of the second act (the party), Zuko pisses Mai off so much that she breaks up with him. They make up at the end of the third act (the campfire), and refreshingly, there is no groveling.