Getting over a breakup?

My girlfriend of 3 years broke up with me. She told me she wanted to be independent and find herself and couldnt do that while being with me. We have had a turmoltious relationship, which culminated in her arrest last August for Domestic abuse. We were not allowed to see eachother for about two months and while she was gone I got us an apartment. We both worked together at the time of the arrest and were subsequently fired soon thereafter. When we met back up everything was great again for a while. She couldnt find a job, so I supported us in every way. This led to a lot of resentment on both sides. On christmas I got druk and we fought again. In april she told me she didnt love me anymore. We still live together..she found a job shortly after the breakup and helps pay bills. I found a note from some dude about the two of them hooking up two weeks before the breakup. I asked her about it and she said that they had been talking since august..that he was a member at our gym and had comforted her when we were apart. She had been talking to him and confiding in him since that point. I still love her and want her back so much..even though she cheated on me. She said my clingyness is pushing her further and further away. She just doesnt feel like she could ever be with me again. She still talks to this guy and occasionally goes out with some other douche. She has anger issues..and has had a lot go wrong in her life. When we met she was a coke head..very permisciuos among other things. I showed her the good side of life and she fell head over heels for me and gave up her bad ways. I always looked at her as the girl that she was even though she changed and I feel that is why she cant find herself with my constant reminder. We were engaged for a long time and talked about a magical future. We would always give eachother one more chance..she abandoned me.. Now everything I was working towards is ruined. I drink constantly..I was on my way to a good career.but now I cant seem to think of anything but her...she just wants to be friends..f that. how do I win her back? How can I get her to fall back in love with me? Im ready now..Ill forgive everything and give her everything I got...I cant let go..I cant let go of the one thing that made me happier then I have ever been!!! I have given up everything just to be with her and now its over...it doesnt have to be right?