He’s still trash.
If she never had the strength and courage to leave him, he never would’ve gotten his act together. He never would’ve listened to her and would’ve continued to neglect and take her for granted. The only reason he’s defending her now is bc he’s losing her, and behaving in such a supposedly honorable way by wishing for her happiness eases the potential strain on his pride and sense of character that would come from stooping so low otherwise.
It’s easy to be the better person when faced with someone like that noble lady who’s so clearly morally reprehensible. If going to the extremes is the only way to get him to finally appreciate her even the slightest bit, then he’s absolute trash