His attitude after sex?

Before sex, he is so loving , so turned on, all over me, affectionate, sweet......and after sex, he acts like he hates me . Tonight I tried to love and kiss on him after we had sex and he looked at me with this face like "uh, what do you think you're doing ?" . He didn't say anything but I definitely got the vibe of " don't touch me, whore" .

Why do guys do this ? Keep in mind we have been off and on (continuously intimate,however) for over 6 years. And after sex he always acts this way. It's emotionally draining.