Oh boy, I'm sure that function was quite something. The xw2 screaming at him after all of these years. He's carried around a lot of guilt for that time. Trying to explain things to her after all of this time is fruitless, but maybe he felt he needed to get it off his chest.
I'm sure if he had told me that he had to tell her that he had enough regard nor to cheat on her, I think my jaw would have dropped. But, you did good and didn't say anyting about it.
I'm sure his S thought he'd better check on his dad since he pretty much created the messy situation by not telling people his father would be there. This function will be discussed by all for quite some time. Jerry Springer would have been proud! LOL!
Take care of yourself.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.