But he seems to have checked out on me even more...
I can say the same about my H.
I think your H is so confused. He thought that he had a plan, like you described earlier. He would live nearby, so you could still be there for him, if he needed, but he would have an OW who would make him happy, and everything would be peachy. I guess it is not working for him and he is realizing it. This is probably why he is angry. He is not ready to have you completely out of his life, so he is experimenting. And I think you might be right when you say that he painted himself into the corner and doesn’t know how to get out of it.
I agree with Wonka, you’ve doing DB perfectly.
M:50 H:52 S28 (my S from previous marriage) M:17 + 3 BD: 06/12 S: 06/12 - H works in another state