You see WB, the problem here is your H's revealing the PAST to you, it eases HIS guilt about what he's planning for the future.
There is no pressure on your part to PROTECT this from happening AGAIN... just talk.. So your H has the upper hand here... He's offered a trifle by moving his desk at work and not pursuing her anymore, but there really aren't any walls built up yet to block OW out... He's not offering those.. He doens't want to most likely...
I would STOP asking questions about the PAST, it just makes him feel less guilty about what he's secretly planning.. and it IS a secret, he's hiding by saying he wants to "get on with his life" etc... thats a LIE
I would pressure him to make some real gestures to show you the affair is OVER and include gensures that will pressure OW to think he's reconsidering divorce...
Real actions need to be taken by him here.. He's just throwing up a smoke screen right now...