Should I get back together with this girl or is she a b***h?

We dated for about 13 months whilst at college, then we both had to move to different cities after we graduated for work. For the first month it was ok and we met up once, but she didn't seem interested in anything I had to say but I thought it would be ok, but then a couple of weeks later she dumped me by phone saying it wasn't working. I was fine with this until only 2 weeks later she got a new boyfriend who she worked with. I was obviously angry so just stopped all contact with her. Then I found out that whilst her and her new boyfriend had split up for a 2 week period, she slept with one of my friends. Admittedly it was a friend I met through her and before we met there was talk they might get it together, but since then there'd been nothing between them and me and him had become close friends. She then got back together with her new boyfriend but dumped him a few weeks ago when she moved to the city I live in now and has been saying she wants to get back together with me. Should I?