I'm afraid my girlfriend may still be loving her ex-boyfriend who broke her virginity. She has always proved that she loves me but I'm not convinced, even though she says she doesn't have feelings for him anymore. Is it true that ladies always have permanent feelings for men they first had sex with?

I am 21 years old and have been with my boyfriend for eight months. This is the first relationship I have ever been in; we had sex only a couple of days after we met and I have been with him since. Obviously I trust him and love him and we have a very healthy relationship, but I have known for a while now that prior to meeting me, he slept with 15 other girls. I have a history of depression and ever since he has told me I have started to feel really horrible about it all - I never thought it was something that would ever bother me, as I have friends both male and female who are promiscuous, but I feel so much differently about it now that he has told me. I feel that it upsets me a lot and I don't know why and I can't understand it. I have tried to talk to him about it a lot but he won't open up to me and I don't know what else I can do.