First of all... the Flyers suck. Go Flames!
Second (and most seriously) of all.... I wouldn't take her back man. If you do there are a variety of things that will happen. One, you will get jealous (justifiably jealous) whenever she hangs out with another guy... it will eat at you and will cause long term anxiety and pain. Secondly, it will show her that it's ok. I dont' know her personality or who she is, but if you dont put your foot down it sends the symbolic message to her that she can do whatever she wants and get away with it. I've seen this time and time again... NEVER ONCE has it ended well. The last thing it will do is send a message to everyone else. People are immature, and people talk about other people, that's what people do well (say that 10 times fast). If you take her back you will be "that guy with no balls". Trust me my Flyers fan friend, it will not work if you take her back. It just simply will not work.
You're too good for people like that. If you put your foot down and break up, it will teach her some lessons and she will grow as a person. It will also prove you have confidence and integrity, and you will get over it and you will find someone else. I know it hurts lots now, but compare it to ripping duct tape off your mouth. If you do it quickly, it'll only hurt for a little while. If you do it slowly it will hurt way more for a longer period of time. Or in this case, if you take her back, that's like re-applying the duct tape all over again.