Re: Issues with girlfriend and past friendship... very long
I'm sure because of her age and inexperience, she has no idea what this guy really is. I think your best bet is to have a conversation with her about how it makes you feel when she not only hangs around with, but defends a person who has done so many things to try and break the two of you up. Ask her how she would feel if one of her "friends", took you aside one day and said that her "claiming" to be a virgin is a big act, and in reality, she slept with the entire football team. Ask her to really think about that, before she gives you an answer.
I would go about this very calmly, without letting it get your "hackles up". It's possible that what she is reacting to is your defensiveness and not really putting herself in your shoes. If she still doesn't get it, I don't know what else to tell you. To me, that would make me think she is just too young and immature to be in a real commited relationship on an adult level. I hope that isn't the case, because from past posts, it sounds like you really have feelings for her.
Good luck and let us know how things go.