My boyfriend masturbates behind my back, even after we've had sex. He knows how I feel about it but he continues to do it! Last night he made an excuse to get up and use the computer, I caught him masturbating again... I relented and gave him a oral and reminded him he doesn't need to do these things he has me. Not 2 hours later he was up in the toilet doing it again. What do you do? Every time he does it, it feels like he's cheating.