Liz, the thing that strikes me right away is that (to me) you both seem to be seething anger. Like the atmosphere must be crackling with it. ?? My interpretation of his excessive apologizing for almost ridiculous things is that it is a passive aggressive expression. (read--passive anger). Not making a value judgement---just saying....
If I am halfway close on this---WOW, it must be emotionally exhausting for you, him AND your son to be in this atmosphere!
I have been in an angry atmosphere like that before and it was awful. I sure do feel for you.
I am rooting for your continued growth (metmorphosis).