Yes, that's one of the learnings here, you should *always* question your partner's intent to continue with you, but from the perspective of what are you doing to make that a good option? Taking our relationships for granted, or feeling our partner "owes us" is a cancer of marriage.
With regard to your H, he's in a panic right now, he's going to end one relationship and knows he risks losing both. He is talking so much about the future and seems to be over his grief because he wants to ensure that you'll stay around. He realizes he's at the point now where he could wind up with no one and he doesn't want that.
At the same time, as you're figuring out, his mind is not quite as made up as he's representing -- that's why it's so important to continue to work on yourself and to DB. More so that no matter what happens, you'll be OK.
You will probably get real commitment after he goes "no contact" with OW, although it's likely he'll still feel confused and torn for a while.
Accuray
Married 18, Together 20, Now Divorced M: 48, W: 50, D: 18, S: 16, D: 12 Bomb Dropped (EA, D): 7/13/11 Start Reconcile: 8/15/11 Bomb Dropped (EA, D): 5/1/2014 (Divorced) In a New Relationship: 3/2015