I still see the religious conflict as a major problem. I think you do, too, or you wouldn't have made that your starting point. You are asking advice on how to improve an experience that you believe is a sin. How can that work?
If you don't want to break up, why not take a defined break from sex while you talk this over? You could tell him you want to take six months off, for instance, from sex. We're very focused on increasing and improving sex here, but I'm not sure that's really what you're looking for. I personally don't care if a 42-year-old adult wants to have sex outside marriage--I assume a 42-year-old will take responsibility for the consequences of her actions. But you still need to make a choice. Either you have sex because you believe that's OK, or you refuse to have sex because you think it's not. You're disrespecting yourself with this and it's making you feel lousy. Besides, as you've already noticed, every time you try to bring up the problems in your sex life, he has the "hey, we shouldn't even be doing this" card to play, and apparently he's found that useful.
