How would you deal with a bitter ex-husband who thinks I don't deserve child support?
Best answer: Tell him the child support pays the bills so his kids don't live in poverty.
Ignore it. OR.. call him out on his anger at having to ASSIST in supporting the children HE produced.
He's ignorant about what child support is. You DON'T deserve child support. Your CHILDREN, deserve to be supported by both parents. Your ex is a moron who thinks that he's supporting YOU, when in reality, all he's doing is contributing to the cost of feeding, clothing and housing his children.
Most men get over themselves when they are educated about what child support is.
You have no control over how he acts. Let him be bitter and resentful if he wants, as long as he pays you the court ordered amount to help support the children he helped create.
Minimize contact with him and if he starts to be unkind or complain, tell him you're aware of how he feels and prefer to keep contact to only what is necessary regarding the children. You don't have to listen to him complain or say ugly things, either hang up the phone or walk away, after you remind him that he's in the position he's in, because he chose to betray you and his marriage. It was his choice to cheat, and actions have consequences.
It doesn't matter what he thinks you deserve, what matters is what the law says you have a right to receive.