For me, she just moved on and is trying to be nice enough and get things done.
You assume she moved on, don't believe its the full case. If it helps you move forward then fine, but she could be thinking anything. My W is nice also and it makes me think shes moved on, but who to really say in the long run if they have or haven't.
So I have a WW who sees her D as a solved problem, with a few steps to go through. It's not always easy, but she's not angry, sending a message or anything. She just finally found someone more compatible and life is good. I'm a good father, so everything falls into place.
All WW's see the D as the solved problem and OM as the solution, yours is no different. You assume they are more compatible but again, in the long run when they aren't in the honeymoon phase with the chemicals driving them, who knows.
Accept what is, let go of what was, and have faith in what will be
