I do my level best for her, but she is so closed.

I have been going out with my girlfriend for just over 2 years now. I love her to pieces, but she has hurt me in the past quite badly and I have forgiven her and carried on with her, even some of my firends were dubious, because I love her so. It is just that she can be so distant sometimes not contacting me for days or just not come to stuff that she said she would. I do understand a fair amount about her now and the problems that she has had with her family and how they have effected her. But I bend over backwards to help her all the time and she rarely does things of that nature for me. I had just always heard that guys were supposed to be the distant ones? Because of this I sometimes end up feeling resentful of her and I don't want to feel like that.

If anyone has any advice on this I would be really greatful, because I really don't know what to do, but I don't want to end with her.