Holy sh**. This is what I like to call porn culture. Your body is your own. So of he is slapping you and biting you without your permission, he's borderline assaulting you. In a bedroom both partners must be respectful towards each other, and if he is not, just leave. It's a nasty way to treat someone. A little bit of wildness is appreciated but not when you are against it. Don't let yourself and your pain be used by him for his climax.