Most good stories start with a fundamental list of ingredients: the initial situation, conflict, complication, climax, suspense, denouement, and conclusion. Great writers sometimes shake up the recipe and add some spice.
Exposition
Total Romantic Apocalypse
If Why We Broke Up were a classic love story, it would begin with boy meets girl. It isn't a classic love story, though, so instead, we sort of start at the end: We know Min and Ed break up before we even see them get together. To determine why, Min will sort through the detritus of their relationship throughout the rest of the book.
Rising Action
An Uncertain Courtship
Most of the book flashes back to Min and Ed's five-week relationship. They fall in love quickly and their relationship is intense, but at the same time, there is always an air of uncertainty. Min feels insecure in her role as Ed's girlfriend, and vaguely suspicious due to a weird vibe she picks up from Joan, Ed's sister. Min also struggles with whether or not she wants to lose her virginity with Ed.
Climax
Ed's a Cheating Cheater
Before we opened the book, we knew Ed and Min had broken up. But it's not until close to the end that we finally learn why: Ed has been cheating on Min with his ex-girlfriend, Annette. Ugh. Min dumps him as soon as she finds out. The climatic scene takes place in a flower shop, and at one point Min asks Ed, "Did you dump me for another girl and I didn't even know it?" (40.81) He doesn't answer, but yeah, pretty much.
Falling Action
Min Deals
Again, Why We Broke Up is not traditionally structured—and this is particularly true when it comes to the falling action. Instead of the falling action taking place after the climax, it actually fills most of the book. Chronologically, it happens after the climax, just like it's supposed to; we read it before we reach the climax, though.
The first chapter tells us that the text is an epistolary novel, which means it's written as a letter. Min's writing to Ed on a day in December, a month or so after their breakup. The letter inventories a box of mementos from their relationship that Min considers one by one. Each chapter focuses on one memento, and through these items we learn their love story.
Resolution
Happily-ish Ever After
Breakups can be emotionally messy, and over the course of the book we see Min deal with all the conflicting emotions her breakup inspires, including love, hate, sadness, and anger. But Min seems to find catharsis, or emotional release, in writing the letter to Ed. As she concludes the letter, she seems hopeful as she contemplates a future without him. Min's not quite happy—yet—but she's definitely getting there.