Prior to getting married, Don and Betty entered into a premarital agreement. The agreement provided that if Don and Betty had children and later divorce that Betty promised to give Don full permanent custody of the children. After 10 years of marriage and having two children, Betty seeks divorce and requests custody of the children. Don raises the defense that Betty is barred from seeking child custody based on the signed premarital agreement. How is the judge likely to rule on this issue and Why.