At what point do I no longer honor the for better or for worse part of our vows.
Now's about a good time.
The only vow your AH is honoring is to his pipe. And as long as that's the case, don't expect him to honor his commitment to you or your children.
He seems to really want to get better
Based on what? His words? How many lies have you caught him in to date? The only thing that matters is his actions and behavior, and you based on those, you've got a clear picture of what he's currently all about.
Protect yourself, protect your children. I would go as far as to change the locks on the doors at this point. Prepare for the worst, and then prepare some more.
Keep us posted.
ZoSo