I can understand your anxiety. Honestly, I know you don't want to hear this but there is a reason your W still has her wall up. She is either still in her affair or she is wishing she was. It's not so much she has a wall up around you, she simply has her wall *around* something or somebody else (or the idea of it all).
IMO your W has always been heading down the path of a separation and really was sorting of trying to ease some tension so that would happen in a more smooth manner. She stresses the things the two of you can talk about which IMO is to show you that co-parenting will go just fine.
While you may have communicated frequently when you both were on trips that is much different than dealing with somebody "live" on a daily basis. Her wall came back up when you came back because you were back and reality set back in.
It seems in your mind you were so sure this would work and you were so sure you were heading to piecing that you sort of missed many signs. I would bet (sorry, I know this is speculation) her suggestion to talk has been in her mind for some time and she waited until your trip was over.
I would only listen to her during the talk and whatever she says (good or bad) you will need a few days to digest it all before you can proceed.
