Name change for children

When I divorced, it was my understanding that our children needed to keep their father’s last name, which I was fine with as it was what they had been going by. My husband recently changed his own last name to something entirely different (foreign, and had a string of family names).

Do my kids have to keep my ex’s last name when he’s not even using it himself? I have full legal custody and full physical custody. Kids only see their father 3x/year or so. Seems silly that they have to keep the last name of a man that has decided to go by another name now. There’s no family link or heritage.

Name change of a minor child requires consent of both parents.