Re your W - you know her better than I do. If I found out my H was on this site I would DB my head off, but obviously your W responds differently.
She sounds really insecure. Did you try the romantic approach or did that not work either?
My H told me once (a long time ago) that his life didn't work without me in it, and I have remembered that ever since because it was such a nice thing to say.
Would she respond to that if you said that next time she asks if you want a D?
What about sex therapy? Have you ever considered going to that? Even just on your own, it might give you a few ideas of how to sort out your M.
I must say I admire your dedication to your M. A lot of men would just walk away. I really like men with standards.