I don't get the feeling that you are obsessing about the possible A, so I think you are doing great. I only mentioned it because I want you to be prepared for the possibility. So many on here, including myself, denied that there was one because the H's or W's were saying there wasn't one in the beginning ... "they just want to be free for no reason other than they are unhappy in the M and have been for a long time ... years even, but only just got around to letting us know now." Quite a shock then to learn they were lying which is a huge symptom of MLC. If their mouths are moving, it is a rare thing for the truth to be coming out of it.
I am not sure what more you could do. Perhaps start refusing invitations? Obviously, what you are doing isn't working unless that's why he is nice on occasion. You could think of shaking things up a bit? Start insisting on regular outings for S4 instead of the sporadic ones he is doing now. Or, you could live with the status quo for awhile and see what happens in a few months.
Take care.
Me:57 H:52 M:28 Got another lawyer last year and filed. D35,S/D twins28,D22 EA4/04 End? Who knows? "Life is like a mirror. Smile at it and it smiles back at you." — Peace Pilgrim