The divorce judge should know the probate laws in your state prior to making his or her decision during the divorce case. It doesn't make sense that you are the owner of the policy that he took out on his life? You mean it's a whole life policy on his life with you as the beneficiary? If he took out the policy and is making the premium payments, then he can change the beneficiaries (following the divorce closing) to whomever he wants. Any reasonable ex would still keep the kids as the beneficiaries through a trust but he is allowed by law to change it to whomever he wants once the divorce is final.
Who's making the premium payments? If the divorce is final , then he doesn't need your permission to change the beneficiaries.