The thing is, your boundary is about what is acceptable to you, not what he does. You can decide you will stick around as long as he is working on recovery, and then you can decide if you think he is doing that. It shouldn't be about telling him what he has to do. The boundary, consequences or acceptance of other behaviour is all up to you.
He's doing what he is doing. You can decide if that works for you or not. He can't manipulate your boundary, if it's about what you will or will not tolerate.
Hugs
Ann