Ok first...you are getting the cart before the horse. Do some reading...go to your meetings and take things one day, one step at a time. Detachment is a complex concept.
Now for your question...I don't blame you at all for not wanting to have sex with someone who is drunk, someone who treats you badly and someone you cannot trust. Your fear is what worries me. You should feel free to say no without fear.
One thing we tell people around here is to protect themselves. If you have one ounce of fear for your safety have a plan in place. Your shoes by the door, cash and keys close at hand, and a place to go. You could probably drive around for an hour and he would be asleep when you get home...or go to a friends.
Hugs,
JT