Unfortunately you can not make him pay anything.
If the debt occurred while you were married to him, it belongs to both of you.
Yes that does not sound well but that community property for you.
“And the two shall become one”
I’m a very strong avocet of cutting all legal ties to those who have no regard for responsibility.
I had to file a beautiful BK in order to get out from under the mountain of debt the my dearly beloved left for me.