I'm having a LOAD of trouble with this myself. I am at the stage where sex is happening, but it has no emotional connection at all. It's pretty much masturbation using another person as the means to the end!
I think at this stage of our recovery sex is like a mine-field! It suddenly develops more significance than it ever did before because there is so much riding on it (geez that is an awful pun right there!) and it is such a touchy topic (ohmyword, I should probably quit trying to write this response right now..."touchy topic" )
What I am trying to say is that the whole issue becomes fraught. Well it has for me. I find myself over-thinking it all the time: "Well I really don't want to have sex with him right now, but if I don't have sex with him, well that is just looking for trouble, isn't it?"...or, "I actually want to have sex, but I am so angry with him right now, and sex would be sort of rewarding him wouldn't it?" All sorts of thoughts go round and round my head. Sex used to be a no-brainer, it's what married people do... now it has all these connotations. It's so complicated! Sometimes a little ahem "self-help" is a much easier option... But I do believe that sooner of later we are going to have to confront all the issues around the actual act... If masturbation becomes a full-time escape from dealing with the issues around the act itself, well then it's no different from any of the other acts of avoidance (refusing to talk about the A etc) It comes back to "you can't heal what you won't feel".