Let me tell you. Don't let a woman walk all over you like a doormat. She will learn that no matter what she does (or who) you'll let her come back. She WILL use that to her advantage.
Being friends will be hard. Trust me. There's too much history. You may want to talk now and again, but when you get another girlfriend, I don't suggest talking to her at all... especially if it upsets the new girl. Once again, too much history. She may try to influence you and your new girl.
I'm being totally serious when I tell you women are emotionally and mentally manipulative. If you say 'No, my girl's not like that' I'm calling you the idiot who doesn't see that you're being manipulated.
Ok, so not ALL girls are like that, but most of them that I talk to are. And this from a female anyway... I've done it. I don't find it entertaining anymore. I get nothing out of it. Once she grows up (if she does, since most just love reaping the rewards of their labors) she'll realize that it's not worth it.
It's a lot more rewarding just being yourself and being loved for who you are. You don't have to hide.
I hope you guys work things out to where it benefits everyone, and I'm sorry to hear about what happened.