You're wife is being strung along by a guy with sexual problems. You don't become impotent from having a fat wife. It may take your wife a while to wake and smell the coffee, but OM is not a replacement for you.
You're doing a great job being there for her. Let her come to you. You don't have to rush over there to do everything. Make it easier for her to just move back home where things make sense.
Don't listen to the whining she does. She asked to come sleep at your house. She shouldn't be complaining about the quality of the sleep. She just doesn't want to accept that things are better at home.
I would give her the sex she wants. I believe that sex is perhaps the strongest link between people. Make it so good he can't possibly measure up. She wants him to be something he isn't. Eventually she will face reality and see the real him. Right now she's still dreaming.
