Hi Sodetermined. Sorry you're going through this. My ex's doc was meth also. I was a good wife, but I got the same lines you're getting about if I'd do this differently or pay him more attention or be better in bed, etc, etc. then he wouldn't do drugs or drink. It's all part of the blame game that addicts use to make them feel better about their addictions. If they blame you, they don't have to blame themselves.
What is your dealbreaker? My ex went to 3 rehabs, jail, then prison. After prison, I'd had enough and when he relapsed and started staying out all night again, he had to go. He was telling me he lived in a rental house about 15 miles away, when really he was living at the drug dealers in a shack out back (no power) with his GF. That was my dealbreaker. After giving this man 18 years of giving giving giving and receiving nothing in return but heartache, then he does this, I know I can never take him back.
If they are not working on recovery, nothing will change. Maybe make a pro/con list of why you're with this man . What you're getting out of the relationship, etc. This will help give you a clear view of your relationship as you move forward and decide to stay or go. Keep reading and posting! It will help you so much as you go through this difficult time. ((HUGS))