My heart goes out to you for what you're dealing with. It saddens me and frightens me at the same time, for I see myself in the same spot in a few years. My AW seems to be on the same slippery slope; she's overweight, sedentary, takes numerous prescription drugs and drinks herself into a stupor three or four times a week. I think it's only a matter of time until she becomes an invalid.
Good luck; I hope you find a way out that gives you peace.