I for sure think you are piecing. I also want to take this opportunity to proclaim the fact that I called it months ago! Lol. I'm not always right about this stuff and even more rarely go on a limb and predict it, but months ago I said I thought your W was coming back and was trying / even though some, even a few of our rock stars here, didn't see it or were not so sure.
I've had a good feeling about your sitch for a while now and think you've got a real shot.
Now, I have to say I have the same sense, same gut feeling about my next comment. I hope this time I'm wrong and only say this so you are prepared. I think your W was intimate with OM. Did they have intercourse sex, not sure but there is no way they just talked about it. At very least they kissed and touched. Oral is also likely if not actual sex. Your W may never admit it for the same reasons she's feeling she's already let others down, including you. It would just be odd that all of this went on, meeting while away, etc. and not have gone beyond hanging out. I just don't buy it. I also don't think it happened a lot or often but I, betting it happened. Further, I think she has confessed this to your C or the C suspects it herself. That's why she's asked what she's asked.
I hope that's not a deal breaker for you, even if I am correct and it is true. So very few of us even got the chance you are getting. It's still going to be a long road home, but I really do think you are firmly on the road and W is with you more and more everyday!
DonH Midwest Me 56 WAW-EXW 55 Met 11/95 / Married 5/00 Bomb 6/20/05 / She Filed on 6/2/06 / Divorced on 10/9/06 4 who'd qualify as GF since D & dated about 25 women since D