Why is Princess Michael not called Princess Marie-Christine?
Traditionally, all wives of male members of the British Royal Family, the aristocracy and members of the public take the style and title of their husbands. Diana, Princess of Wales was not “Princess Diana” as the media called her, because she was not born a British princess. Her correct title was The Princess of Wales and when she divorced she became Diana, Princess of Wales. When the present Duke of Gloucester was still Prince Richard prior to the death of his father, his wife was known as Princess Richard. It just so happens that Prince Michael is the only grandson of a king titled HRH who is a second son and so there are no other princesses with the name of their husbands. The other princesses in the British royal family were all born into the royal house.