Sleeping with a lot of people will not make you even. It will only drive the wedge wider. You need to figure out if you can forgive her. If not, you need to let her go so she can find someone to love her as she is. No matter how sorry she is about her past it can't change facts. It doesn't make her less of a person because she slept with many men. People change and regret past mistakes and they should not have to feel guilty for the rest of their lives because they made some mistakes.

This is sensitive to me because I am like your girlfriend. I made a lot of bad choices and was punished by my ex-husband for years and made to feel less than. Even after I left him I made mistakes, but my current husband understands that the past is the past and needs to stay there.

I hope you can work this out. You sound like a really sensitive guy. Remember she has feelings too. Let her grow from her past. It doesn't make you less of a man, nor does it mean she will make the same mistakes again.