I think that when a couple separate and divorce, they should avoid keeping in contact with each other. This will just cause confusion. When 2 people divorce, that means that whatever the other party does is no longer the business of the other.
Let him live his life and live yours. You can never be good friends with an ex.
Move on with your life and find someone you will be happy with and stop looking back and paying attention to your ex.
Best wishes to you.