GWN,
We don't know what the future holds for any of us and who knows...he may come home at some point. We just don't know.

The small talk and bringing up things that you did is his way of "reliving" the "old" life and he will revisit that life quite often in the days ahead as he travels through space. In his mind, he is still trying to find a jusitification/reason for why he left and the way he feels about you right now. Unfortunately, there isn't a justification for his behavior except that he is unhappy w/himself.

Time will tell as to what happens next w/him. Give him plenty of space and do not contact him unless it is an emergency.

Just breathe a sign of relief that the day is over and look to tomorrow for new adventures. I am very happy that he behaved himself.

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.