I dont think the first ones to find out about an OW woman would be the kids but hey, my H introduced his OW to my son while I had no idea we had issues (yes, I know, stupid me!).
Anyway, you sound a bit better. Dont allow him to play mindgames with you and that would be something I WOULD make obvious to him as well. Like telling him "wow, you are wearing the shoes I bought you, I do have good taste afterall, in shoes at least!" with a smile and go on doing what you were doing. I would and actually did, be ecxited in front of the kids about their visit with dad, showing relief you get a chance to have time on your own, for me it was true after a little while so it wasnt faking it.
flo, something we LBSs seem to forget is that WASs are HUMAN. They do notice things and do get affected by our actions and recations as well. It may not show -not immediately- but trust me, there is NO WAY, any seed you plant in his head, not to occupy him. Of course they have to face, pride, egoism etc etc so they would go out of their way not to make it obvious. They are DBing us better than we are DBing them.
Next time you see him, FEEL the power you have over the situation as far as YOU are concerned. Dont hand it over to him in your mind because they sense it like dogs sense fear.