Boyfriend's Sex Drive Dropped

Hey guys- I am feeling horrible right now. My boyfriend and I have been going out for two years now. I have had a bad relationship with pornography in the past due to ex boyfriends being addicted to it. He says he can't watch it anymore and for a year he has told me he doesn't even masturbate. I told him countless times I don't care if he masturbates, just as long as he doesn't watch porn. I found out a few days ago that he has been masturbating recently, and he tried to lie to me about it, but I just told him to be honest. Now, he admitted to having done it once a few months ago, and I don't care but I don't like the way even after that 'one' time that he proceeded to say 'I don't masturbate ever'. Anyway, ever since I found out he does do that again, he hasn't been as eager to have sex or play with my body. On several occasions this week he's left having sex until we have said goodnight in bed and I've had to say 'are you going to have sex with me tonight?'