I have had very very similar experiences with my W - times when we're together - usually at some event connected with our S7 - as we were last week when attending a Parents' Evening at school and then S7's investiture at his Beaver Group - we saw a few other parents there - and got into a couple of conversations with other parents - during which it was as if the stuff that has happened over the last couple of years just never happened...we were able to laugh, whisper, share stories, observations and so on...and interact with other mums/ dads in a way that made me feel like we were still a couple with intimacy. It was very weird.
Yet at the same time I know she has an OM...
And I the majority of these other parents know this too...oddly, I didn't feel that it was difficult to deal with that evening - in fact I enjoyed it immensely - rather than let it get me down I saw it as a challenge to rise to...and was pretty pleased that I was able to. W also seemed very relaxed and game in the same way.
What I have learnt though - as you observed up-thread, is not to read anything too much into it...but to enjoy the moment and then leave it. I had exactly that same experience - I almost had to pinch myself to make me remember that this person who I was whispering to, sharing stories, thoughts and so on with - was a woman who a year ago was screaming at me that she was trapped, with no place to go...that it was all my fault, that her life was over and if it wasn't for S7 she would just leave and I would never see her again.
Previously, I would have followed that up with something - an email, a text - by being grateful in some way but never appreciating the underlying message of "hope" that such a message would convey and consequently how destructive that would be.
Its been a hard lesson - that every such interaction or approach from me was destructive - but since I have dealt with such interactions in that way, i.e. enjoy them for what they are, offer the validation and mirroring when "in the moment" (thanks to 25mlc for that) and then to leave it, the feeling I'm left with is much more satisfying and not undermined, as was the case when I went the extra mile - which after all, was then more about me and about my needs and wants.
By learning this and adopting this approach, things have got better for me - inch by inch; its like mastering another level of difficulty - achieving a greater level of competence. It may not result in W and I reconciling, likely it won't, but right now I concentrating on achieving a balance for me.
Smiley - when I first came here - I was struck by David's post on the front of this board - and while its taken me a while to even get half-way to his way of dealing with things - its something I still have as a goal...At the very least it will give W and I a basis from which we can ensure that S7 always feels secure and loved.