Scott at 2016-06-15 00:20:45:
Here is a breakdown of the story's plot using some song titles as themes for each sequence:
Love is a Battlefield (1-12): Intro Nancy and establish her dysfunctional romantic life.
I Want to Hold Your Hand (12-20): Nancy intersects with Jessica, the whole book thing, and the meet cute with Jack.
Liar, Liar (20-34): Nancy learns to adapt as 'Jessica' and is almost ready to confess the truth, but doesn't.
It Ain't Me Babe (34-53): Bowling is a blast and the couple is flirting big time, but when Sean enters the scene, the truth comes out.
You've Lost That Lovin' Feelin' (53-66): They head back to the Mexican bar and Nancy has a down moment in the bathroom alone, only to emerge to see Jack's ex-wife with her new beau.
Gimme Shelter (66-83): Nancy takes on the role of Jack's fiery lover giving Jack cover with his ex.
One is the Loneliest Number (83-91): Jack bumps into Jessica and goes off with her leaving Nancy alone and crying at her parents party, and Jack unable to keep his mind off Nancy.
Help! (91-98): Jack heads off to find Nancy getting help from Sean, who fools him by dropping off Jack at a teen party while Sean heads to Nancy's parents house posing as Jack.
I Want You (99-108): Jack finally makes it to the party and confesses his feelings for Nancy and she him.
As always, I have to note, these are arbitrary, you can interpret the structure in any number of ways. Indeed you can break down the above sequences into even smaller ones. But this is a decent take on the story's plot.