Thanks for all of the advice. Yes, I still do agree with the fact that he shouldn't have let those women stay with him. I know I am insecure and have "baggage" but I think most people would have a problem with that.
He has been cheated on in the past too, and he has been insecure with me as well, so I was partially hurt that he wasn't more considerate. My best friend is a gay guy, and he was weirded out by our close relationship. When we first started dating he even demanded to meet him to make sure he was really gay! So, I think part of the reason I reacted like I did was frustration that he was not, for lack of a better word, "respecting" my issues.
I really don't want my past to dictate my future though, so I am in therapy. It has helped me a lot, but unfortunately it seems to be a slow, ongoing process:(