I also recently got divorced.
The only advice I can give you. Don't concentrate on these matters that he does in his personal life now. As you are separated or divorced concentrate on YOUR life and things that make YOU AND YOUR GIRLS happy. Don't feel miserable about the things he does in his life, because this is not your life anymore.
Maybe with time passing you can at least be friendly to each other.
I would say be happy that he could leave the jw thinking and that he can enjoy his life outside of the watchtower. This way your girls can also benefit as they can spend time with a happy dad and that they will not be indoctrinated when they are with him.
Why didn't he act like that when he was with you?
Maybe because like you he was also a Watchtower victim.
But the most important advice I can give you. In front of your girls speak positive about their father and strengthen their bond with him.