Monk, Sorry you're in this situation. I do see some things that might be worth a try for your situation. The fact that your wife does see a problem and does regret that the problem exists is very positive.
First, I expect that your W doesn't really fully understand what sex does for you because it doesn't do all those things for her. But that is about her and you only have control over you. So my suggestion is that you really show her what it does.
Quote: In any event, I am really getting turned off the idea of having sex with someone who obviously has no interest - particulary if it would only be out of some pathetic sense of duty.
Let's take this statement of yours. Let's reframe "pathetic sense of duty" to "She's doing this as an act of love. She is doing this for me. She wants to do something for me because she loves me even though she struggles with a lack of desire for sex."
Now, how would you respond to someone who has gone out of their way to do something for you as an act of love? Would you express dissatisfaction? Disapproval? Resentment? If you did, do you think they would be highly motivated to do it again? Do you think their attitude toward doing it would improve or deteriorate?
It may not be exactly the way you want it right now. But if you want her to continue trying, if you want to see her try more often, if you want to see things improve, you've got to give her a reason to keep on. After you get some duty sex, be very happy with her the next day. Be very attentive, loving, listen to her, share good feelings you have toward her with her. Do extra chores,...whatever you know really floats her boat, go overboard with it. Be so amazing she wants to know why! Show her what sex does for you. Don't hold back the positive stuff. Bury the bad stuff that "duty sex" causes in you. Yes, bury it. The bad stuff isn't going to get you more passionate, willing sex. It will only get you more "duty sex" and probably less of even that.
Make her WANT to have sex with you because of the person you become as a result of having sex!
Second, lubrication, lubrication, lubrication. When you do have sex, make sure there is plenty of this. Think you have enough? Use more. It's not just a matter of comfort. Lubrication is a sign of arousal. Using artificial lubrication when natural lubrication doesn't occur easily mimics the arousal state and the brain can respond with messages of "I'm feeling lubricated. I must desire sex." The state of arousal comes before the feelings of desire for a whole lot of people. If this doesn't happen as naturally as it used to, go for help to mimic it.
