I only enjoy rough sex?!

I've been having sex with my bf for over a year and I only really enjoy the sex when it's rough and hard. When he goes slow and its romantic I never feel like I'm going to cum. I mean it does feel nice but not nice enough to make me cum I guess. I will admit that his dick isn't huge, it's average size and I've always wondered if that is why or if I'm just weird or slutty for only liking it rough...?