Well, there are cases where people actually love you very much, but inside are afraid of being hurt by them. He may love you too much to where he'd be way too devastated if you left. Therefore, he feels certain that he needs control over you so it doesn't happen. Either that or he's just a jerk :/
Because he feels he is allowed to be. If his "mean" behavior is not confronted he is going to assume that it is ok with you and keep right on doing it. If you don't like the way he is treating you, it is important that you tell him in clear language what you expect. If he can't meet your expectations and treat you as you deserve to be. Walk away. He is not mature enough to be with you. Find someone who will treat you with respect.
If it's an everyday thing I would start being mean back..or jus tell him how it bothers you when he's hurtful..I have an amazing boyfriend but he gets in moods that can jus be hurtful and I jus tell him how I feel and he normally apologizes :) if u have a good guy who loves you he will understand
Be very careful. Most abusive relationships don't start off with the guy beating the carp out of the girl right away; it progresses from insults, belittling, verbal abuse, and being controlling onward.
I suggest you get out of the relationship now. Especially of he tries to make you feel like his hurtful remarks are your fault or that you deserve it. Classic early signs of an abuser.