Okay, I'm going to be incredibly blunt and opinionated.
*An orgasm is temporary. There are many gadgets that are dedicated to female pleasure on the market. No, it's not the same as sex, but you don't have to have a baby or deal with emotional manipulation. Put bluntly, don't be a slave to your sex drive/physical affection addiction. Seriously, a kid is going to last longer then a dry spell.
*From reading your posts, you don't want to marry him or have a kid with him. At least not right now. Do you think he'll make a good father? Do you think you'll make a good mother? Can you see yourself raising a family with this man? If you're thinking "no" or "I don't know," then this baby thing ain't going to work.
*If he's pulling this crap now, he's going to do it if you guys get married and have kids. Anytime he wants to get his way, he'll use sex. Is that what you want?
I know it's easy to say this from the outside, but walk away. Or at least take a break from the relationship. Buy a Hitachi Magic Wand and get a pet for company. He's not the only person in the universe that has a penis.