Oh and because I didn't write a long enough novel above I also wanted to add something about the other-validation stuff Ganb8te mentioned and what you discussed about continuing to be nice to her.
My H is the same. He is looking for external validation and that is why he is trying to conquer as many OWs as possible and searching for it in his party lifestyle. And yet coming back to me for security, comfort and validation too.
And like you I could tell it helped both of us to have a nice fun friendly relationship so I kept doing it.
Guess what Mozza? He still kept looking for OWs and trying to talk to me daily. No.
Indeed she wants affirmation and friendship from you. But you have to do the tricky thing and show her you CAN do it but you choose not to because she is not your wife right now. She is someone else's girlfriend. You don't validate and affirm someone else's girlfriend, right?