What If? (2014)

Wallace (Daniel Radcliffe) meets Chandry (Zoe Kazan) at a party.  They banter back and forth with each other, it all seems to be going pretty well, and he walks her home.  She gives him her number at her doorstep, and then lets him know that she as a boyfriend.  Not just any boyfriend either--a boyfriend with a capital 'B' who she has been living with for five years.  So he loses her phone number.

Only it isn't that easy to give her the slip. The first reason is because she is the cousin of one of his best mates and the second is that he keeps running into her independent of that.  Don't these people know that when that happens it is true love?  No they do not.  So instead they deny their feelings for each other because she doesn't want life to be confusing and he doesn't want to be the guy who breaks up a long term relationship.  The dialogue is just as clunky and messy as real life, and this movie careens along, alternating between funny and painful to watch until the two of them figure it all out.