Forgive me for being blunt, but if you're never going to be able to reconcile your girlfriend's past with the person she is today then I think you should find somebody else. Her past is what it is. Many people have difficult pasts and engaged in questionable behavior earlier in life, only to grow and become better people for themselves, myself included. If I found out that my girlfriend harbored irremovable disgust for me, that relationship would be ended. No question. Your girlfriend is not two people and you cannot successfully treat her as such. She is the singular evolution of her own life. If you honestly feel like you can't deal with that, then do both parties a favor and move on.