Have you ever seen someone in so much pain, or so sick, that they become delirious? And in so doing, would you agree that their ability to rationalize and think clearly is skewed?
I'm not accusing you of being off your rocker, no worries. I think you have been living with a great deal of pain, and you've been living with it for so long, you really have no idea anymore how much you are actually hurting. But you do have a bit of tunnel vision, and that is a hyper-focus' symptom that can accompany a great deal of pain.
Because none of us know you IRL, there is no way any of us can really 'help' you. But if you trust any of us, and you really do want to stop hurting that much, you are going to have to trust me, and others, when we say that you are going to have to help yourself, and get some help.
You've got a lot of 'hurt' that needs to come out of you if you want to heal. I'm not a doctor, I can't set a broken leg, but I know if I break my leg, I need a doctor to set it. Otherwise, my problems will only get worse.
I think through the professionals on this web site, you could find a really good shrink in your area. The only problem is, if you aren't willing to go, or you aren't willing to take the first step... there isn't really anything we can do about it.
My xH is/was a lot like you. And the shrink saw the same thing in him that I think I might be seeing in you.
If you can get the help you need to stop your hurting, I think you are going to see things in your life/marriage/wife in a whole different way... you will see options you couldn't see before.
The intensity/frequency of pain you are feeling is the initial problem. That can be fixed.
The desire problem is issue 2. The desire issue may have caused the initial pain/wound, but now you have two problems instead of one. You have to heal the infection (pain/hurt) first, in order for the wound (lack of desire) to heal properly.