I think several months ago we chatted a bit about your moralizing tone at times toward W. That is what I was thinking about. With your separation and decision to open the door to dating, you really for the first time gave W space to figure out what she wanted, free from the guilting/shaming vibe of the previous situation.
Now, no doubt the idea of you dating stirred up some jealousy on her part, which can certainly do wonders. But I think that as much, if not more, of the change has to do with her finally being in an uncoerced context in which she can finally see what SHE WANTS herself rather than feeling pressed to conform to the role of "the good wife" who dun wrong and who "has to do" as told by her husband who seems to hold the moral trump cards.
Like I said, the tricky part will be for her to re-enter a committed monogomous R without her feeling that internal stifling pressure to conform, even if you yourself continue not to supplement the pressure with external guilting/shaming.