Something blackfoot said to you over on Mojo's thread got me thinking...
I would describe 'arousal' as a physical sensation, whereas I would describe 'desire' as an emotional feeling. You can experience those two things together, or independently. Often, one can trigger another.
I think your emotional desire for affection/emotional closeness with your wife triggers in you physical arousal (or, it could, if that all took place).
When I was LD, I experienced impulses of arousal... and when I did, I MB'd. It satisfied the physical hunger, so to speak.
The reason my emotional desire to share my physical arousal with my xH was absent or very low, was because we could not find a way to forge emotional connection. The vulnerability experienced from an emotional connection is what creates intimacy during sex.
Otherwise, it's just fcking. There is nothing wrong with fcking, btw, but it isn't necessarily emotionally satisfying.
A lot of women say that they want romance or romantic sex. I believe that is Woman Speak for "I want to emotionally connect with you," for often, when you are having a 'romantic' dinner, you are forging EC. If you don't, you think of the 'romantic effort,' as a bust.
So. Let me throw something at you, and see if this makes any sense to you. Take a look at the EQ for Everybody site.
I think if you get really good at that, if you raise your EQ... things will start changing for you. You will create a win/win environment for both you and your W.