Could it be that although you had a lot of sex with people from the past that these were people you had no desire to have a relationship with? And did you find that your true friendships the ones that lasted were the ones that were not sexual in nature. Plus, it could be that you see the men that you did have sex with had not respect for you and viewed you solely as a sexual object, and that is not what you want in a long term relationship.

I agree with the others that it seems more like a mental/intamacy thing. How to fix it, I do not have an answer. I do wish you the best of luck. I also know that the added pressure of a demanding partner can be overwhelming on a mental level and only make matters worse.

I wish I had a magic answer to this one. I would not recommend you just go thru the motions to appease him, as it is degrading to you but i can also see how this would be a strain to your relationship.