Sorry for your situation.
The couples therapy doesn't seem to be doing what you had hoped for, and also a person needs to wants to change, your husband does not.
I know you want what is best for your children, but do you want them growing up thinking this is what a marriage is suppose to be like? Then you will agonize the whole rest of your life as they have unhappy marriages also, and blame yourself?
If you don't want to tell him to leave for yourself, do it for them. Children would rather be from a broken home, than live in one.
Kick him to the curb, if he won't go file for divorce. No one should treat you like that. You seem like a nice person. You are going to make yourself sick over this. What are you waiting for?