LOT...
I could have written much of your post. My STBXAH doesn't get it either. He asks me the same things " How can you just throw away the last 8 years of marriage?" "Why are you doing this?" "I need you to help me" "Those people are brainwashing you".
He signed our dissolution papers, but keeps threatening not to show up for our court date, which is Monday. If he doesn't show, they will throw out our dissolution. I've told him in no uncertain terms that if he does not show up to finalize it, I will immediately file for divorce. The only thing he will accomplish is costing us both atty fees and dragging the whole thing out for at least 9 more months.
I have tried to be "nice", but have had as little contact as possible. We have no children together so at least I don't have that issue to deal with.
I stopped trying to make him "get it" a while ago. All I want is for him to show up to court on Monday so I can move on.