That's been the case with a lot of older men I've known. No sex at home, and no, most of them don't support to him doing anything with anyone else either. They just expect him to accept a sexless life. So, he doesn't want to get hooked up with another woman and deal with all the drama that comes from it. They just want to get their dicks sucked and having a male friend with benefits fits the need.
No my wife is not done with sex but has stated to me if she wants it, she will ask. Yes, I do have a m/f couple to enjoy as well as 3-4 other men to share oral experiences with, nothing has changed there. My wife is struggling with arthritic knees, has for a number of years that makes having sex more difficult for her to enjoy. She helped to masturbate me the other day on the couch, fondling my balls and fingering my ass while I stroked too an enjoyable explosion. She wants me to enjoy the many options available within our circle and I do, I just miss being with her too but have been reassured not to worry.