This happened to me 2 weeks ago. And trust me, I'm one of the nicest guys I know. I always treat girls with respect unless they push me way too far.

>Best friends with girl for 3 months
>Turns out she likes me too
>Date her for 4 months
>2 weeks ago, she talks to her ex-boyfriend again and still has feelings for him, is honest and breaks things off with me
>Not even mad, I still planned on being friends and moving on
>Find a fuck buddy because I've got 5 months left in this town and I'm not looking to form any new relationships
>Now apparently I'm an asshole despite me being nice through everything and putting up with her severe hormonal shit (serious PMS, OCD, all this shit) for months and she starts to try to insult me personally (by typing out a paragraphs long rant on some random guy's status on facebook that I commented on, bat shit insane stuff right there)
>Call out every single one of her insecurities, call her an immature, hormonal bitch, destroy her, tell her to fuck off and grow up
>Laugh every time I pass her in the hall

Feels good bro. And the new sex is so much better.

TL;DR - I "escaped" the friend zone, doesn't help, relationship was seriously unhealthy and we both just chased after each other nonstop for those 4 months. She dumped me for her ex, then tried to make it look like I was the ass. Bitches be crazy so I treated her as a bitch deserves. and I'm a stereotypical "nice guy"
nice guy.