Was there a written divorce agreement? A verbal agreement is not worth the paper it's written on.

Given that the ex-husband would be paying for both policies, it seems that he should have arranged to own the policies, or at least co-own them, so that he had to agree to any changes. And it does appear that he never knew of the change, otherwise he would not have kept paying the premiums.

Going back in history, what was the life insurance for? It seems to be in the low 5 figures, which even 20 years ago would have been little more than a goodwill amount. Instead, it is now leading to badwill, regardless of how the issue of beneficiary is resolved.