Really need to vent break up frustration

1

So my girlfriend (ex) of 2.5 years left me about a 5 weeks ago now (about Nov 5th). She said she was sick of the way I treated her and she “needed time” to see if she was making a mistake. We live together and share a bed so needless to say it has been a very awkward and hard break up. Of course I did the stupid thing and basically begged her to take me back. Immediately afterward this guy I had been friends with for about a year and her start hanging out exclusively, he never comes over to hang out anymore. After feeling horrible for a couple weeks I started to just try and ignore her and I actually felt a little bit better. I go out with friends all the time and we have a good time. I went to visit family for Thanksgiving and when I came back find out she had a one night stand with some random dude from one of her college classes. So then I really start to feel bad, still feel like a wreck about it right now. The worst part is I keep doing things that I know are going to send me into a world of pain ie checking her facebook, taking peaks while she still changes in front of me, and trying to talk to her about what happened. The break up thus far doesn’t seem to matter to her at all. I was talking to her about that friend of mine she hangs out with now and when I brought him up she got this sly little smile on her face and said it was obvious she had a thing for him and that she started having wandering eyes a couple months before she broke it off. I asked her why they weren’t together and she said he probably didn’t feel the same way about her (yah right) and that there were a few other guys she was interested in already, but that she definitely didn’t want a boyfriend. Taking the implied clue on that statement, I started feeling even worse. I asked her if she left me for that guy and she got really pissed off and told me I was kidding myself if I tried to think that she left me for someone else and that she left me because I “abandoned her” and she didn’t like how I treated her. Thankfully she moves out in 5 days, but I feel worse about this than anything I’ve had to deal with in my life. I just finished college and can’t find a job, and meeting new women seems impossible right now because I feel like such a mess. I really wish I could go out there and just find a new flame like she has. Does anyone know where I’m coming from with all this? Anyone else with similar stories? I feel like maybe getting all this out would help me.