I got called away earlier, but Cyranoak, I was going to make the same point of you about how sad (and other words!) it is that so many people are missing out on great sex AND being blamed for it.
I said earlier that "no is a complete sentence". But perhaps "No, I don't fancy you" is more applicable in this scenario. Pretending doesn't help (and makes me really sad to hear about) and also is a form of enabling, I think. Admitting that you aren't attracted to a drunk and someone who is disrespectful is NOT a failing. Leave the ball in their court.
I think that some people have taken those articles that say that no sex is bad sign in a relationship and taken it to heart, yet turned it on its head so that as long as they are having sex, then things can't be that bad. And then, if the partner can be persuaded to have sex once in a while, all is hunky dory. My flesh is creeping as I type this.....