Trying to understand

I have met this guy a couple of months ago and he never did hide that he is a player, who is sleeping around. He also tried to sleep with me but I told him right at the beginning that i am not that kind of girl, but we continued talking on daily basis. As months went by, i've started to realize that besides the obvious problem he is not as bad as i thought he was and i said to myself "what the heck, you're single, go for it". And here things became weird. He told me, that he can't sleep with me, because he would feel guilty and that he doesn't wan't to ruin our relationship. And after that....silence. Try to help me understand please.

Mika