Is he depressed? I assume he has no friends or hobbies since you moved towns for your work. Does he work?

I think you need to give it a chance. I don't know if you've been in a relationship that lasted more than 3 years before, but you should know it's normal for the physical attraction to subside. The butterflies in your stomach are bound to go at some point.

That's not to say that him being overweight and addicted to tobacco, alcohol and food is normal. I think you need to try and help him if you care about him af all, even as a friend.

• Maybe try to get him swap cigarettes for an e-cigarette and nicotine chewing gums at first. Stress to him continuously that it's ruining his health and makes him smell bad.
• Educate him on the importance of a good diet and exercise. You can watch some excellent (can't state that enough) videos from a YT channel called 'What I've Learned'. He adresses the science behind nutrition, addiction, exercise, good sleep and other things. For some things it turned out to be eye-opening. My sweet-toothed, stubborn husband quit sugar completely (and lost most of his extra weight as a consequence) for a few months after we watched his videos on sugar.
• He can try swimming even if he has knee and back issues - it's very beneficial for the back.
• For sleep issues, he could try taking slow-release melatonin. Also make sure your bedroom is cold and well-aired.