I dated her for not too long, about 6 months, she found me after I was replaced by another guy in a close friendship and we got insanely close immediatly, I am pretty naive and what people call a hopeless romantic, so I fell for her hard, she talked about marriage 3 months in and honestly I just let myself believe all of it, however overtime she started getting more and more abusive, she started talking to this guy who she said was just a friend and after about 2 weeks I just kinda let it slide. the abuse got really bad so I  broke up with her a month and a half ago, she then proceeded to attempt suicide and get hospitalized, promise change, therapy, meds, etc, pulled me back in that way and we were on and off for a little while.

A few hours ago I just found out she fucked her "just friends" guy right after getting out of the hospital, I confronted her and she basically said it's not cheating because we were broken up, HOWEVER we were still working things out and talking the entire time, constantly saying we love each other and wouldn't want anyone else, I even asked her if she had been interested in anyone else or something and she constantly denied it, I just don't understand why she would do that, and then lie to me about it, she kept hanging out with the guy during our entire on and off period too so I have no idea what the fuck else they did, I trusted her on that they were just friends the entire time, this is so stupid. It's cheating but she can claim it isn't.

I once told her a girl flirted with me, I got a Nuclear fucking episode, but I can't be upset about this because "It wasn't cheating :(" I confronted her already, told her that we are done forever and she is a cheater and blocked her, but I feel so pathetic, so stupid, and she didn't care at all, I basically stuck there while she got over me and had me as a backup and she was fucking this other guy, while also telling me she wanted a family with me the entire time, I'm mindfucked and don't even know where to begin