But, I have to be honest here. This looks to me like the same pattern that's been going on for years now. You get fed up, ready to bail, and he senses it. Then, all of a sudden, he changes his behavior. (Probably out of fear that you are really going to leave this time.) And then you start changing what you're doing, changing your plans, and giving him *another* chance.
It appears to be his M.O. He is a brilliant manipulator who has managed to keep you off balance and holding on to "hope" for a long time. I really hope I'm wrong about this, but it just looks like another strategy of his from where I sit.
Ditto.
And my STBXAH was a hope dealer too. He always figured out whatever it took to keep the gravy train rolling and everyone in his life just charmed or threatened enough to keep from taking action against his using routine. He was all charm and goodwill until you pushed at his addiction a little bit -- found a hiding spot, insisted on him committing to this or that, erected or enforced boundaries in the home. Then the crazy was back on... until it was time for the hope show to start again.