Moira,
As I was reading your first post I had to look to see if my name was attached as the experience is so similar. My now xnh had all the same issues, but kept it hidden from me for nearly 20 years. For most of that time we had a very limited sex life with him making all the same excuses. When he finally decided he was leaving me for another woman, he started admitting to his deviate behaviors--extensive viewing of porn accompanied by masturbation and finally moving on to having an affair. At one point he was getting testosterone injections, but claimed they didn't make any difference (this was years ago), but finally admitted that they had indeed worked, but he just watched more porn and masturbated more often. He became impotent with me and eventually started taking Viagra. Toward the end of the marriage, he would basically have to masturbate himself to an orgasm and would not let me touch him. My T thinks there are probably many more behaviors he engaged in that I will never know about. The woman he left me for is married and after nearly 2 years, is still married. I don't even know if they are still together, but he will probably choose women like that forever more because they are not truly "available" and there is no risk of intimacy.
I went through a period (at the end when I was stupidly trying to save the marriage), when I allowed myself to dress and behave in ways that would be exciting to him. We engaged in a great deal of sex during that time because 1. He had already decided he was leaving the marriage and I was no longer his "wife", and 2. Because he could view me as one of the whores in his porn movies and I became, as you said, just a vessel. The most disturbing part is that his degrading and humiliation of me gave him great enjoyment and pleasure.
Thank God I had a T who could explain all this to me (he did see my xh for 6 weeks) and finally explained that he was an n. Otherwise, I would probably still be in a state of shock and blaming myself. I still go to therapy twice a month, but after nearly 2 years have gotten beyond the loss of my marriage and am just concentrating on me now. I hope you can do the same.
It is scary to start moving forward and meet new people after this kind of experience. I do think I have learned a lot in therapy and will be much more aware of the red flags going up. Only time will tell.
Blessings,
Brigid