Joshy, I know I had this issue when I was younger. I'm so not hung up about it now, but that's probably because I'm older and jaded. :P I think Leed is right--the others are over her now and don't give her any thought. If say, you were a virgin when you met, it would make a little sense but you've had experiences too so it's not fair for you to judge. she could do the same but she isn't.

are you trying to sabatoge this relationship by chance or do you really want it to work? I think the counseling for you is good suggestion as well. you realize that you are behaving in a way that isn't fair and I think you need to figure out why. best of luck to you and your gf!