Thinking of you. Know also that he may feel that he has done so much damage to your R that it is not fixable in his mind right now. I know my H has said this before too-- he can't imagine me ever forgiving him or him ever forgiving himself. There may be that element to it also.
And, your H has bought so deeply into the idea that your M was over that it might not be that easy for him to let go of it... in fact his ego may not let him. Think of it this way-- if his story is that your M wasn't working and wasn't fixable and he turned to the OW, it makes him less of a bad guy for cheating because well your M was doomed anyway. If he admits to himself that the M is fixable, then it makes everything he's done so, so much worse. So by maintaining he's going to leave is also kind of preserving his own sense of self and his vision of why he did what he did. I'm also going to guess there are some control issues going on there-- he wants to make a decision for himself, not bounce back to his W because OW opted out of the A. (And honestly that is still probably for the best, right??? You have said that over and over. He needs to see what he's losing before he'll come around.)
Stick with it, WF. You can totally do this. You're the very best at it. And all the same things still apply that applied before-- you still have the gift of time; marathon not a sprint; actions over words. He hasn't left yet. He's been going through a lot of mental hurricanes in the last couple of weeks. Give him some space and let the storm die down a bit and then see where you are in a week or so.
xx M (((wayfarer)))
Me (46) H (42) M:14 T:18, D9 & D11 4/19 - 12/19: series of escalating BDs 9/20 - present: R and piecing