I just did the same thing! Here is my replyon your old thread
We can only focus on ourselves. But if we can find it in us to be kind, I think it helps.
At least it doesn't fuel the flames more!!
I never defend myself - I did for a long time but found that going on the defensive (or the offensive) doesn't work.
I think they can't live with the guilt until they deal with it. If your xh is prepared to engage, therapy would be good - someone to talk it out with, and face up to some issues. But mostly the avoidant behaviours that brought them to this place persist.
They have these moments of clarity when we think 'ah finally they have got it' but until they own it, they aren't there.