@Greenpictureframe - that's tough. 
It does sound very much like he is all me, me, me. It's not great that he's cheated on you previously, and has been nasty to you (sounds like a real catch!
)
If he knows he isn't putting the effort in, and hasn't changed, do you think he ever will?
He doesn't want to have sex with you in a position that he can look at you? Sorry sweetie, but that's really not good news. I'm willing to bet he fantasises over someone else... Sorry hon- hugs and more 
He starts masturbating and gets you to take over? Oh dear...
Here's the thing - you are absolutely not a piece of meat, or a living sex toy. You have needs and wants, just like him, and if he doesn't see that, or appreciate you for what you are, maybe it's time to leave.
You could consider couples / sex therapy, but you both have to want things to work, and I'm not sure he does - after all, he's getting everything he wants (I bet he doesn't help out much around the house!)
Maybe start by saying no sex until he pays you some attention, and I don't necessarily mean sexually, but maybe just pays you a compliment, or take you out for a meal, or just talk to you like a human being!
You have a tough time ahead if you really want to stay with him, but ask yourself if life could be better.