Your marriage had reached a crisis point because of your inadequacy in bed, but this new therapist that your wife recently started seeing seems to have quickly figured out exactly what your wife needed to be happy.
My wife has sent me pictures of herself that were taken by her boyfriend while they were out on a date. My all time favorite photo was when he took her to a romantic bed & bedfast and he took a photo of her laying on the big four poster bed in their room. None of the photos were risqué or naughty (she was fully clothed in the picture of her laying on the bed), but they are still the most incredibly erotic photos in the world to me.
It really would be the fairest arrangement, and it’s not like you’d have the strength to refuse anyhow.