When A "e;Good Thing"e; Turns Out To Be B.A.D.!

A royal kingdom is shaken at its core by the choice of its only heir who was to rule the kingdom after his father's death. It was the family's tradition to give the firstborn son a name that would be indicative of how he would rule the kingdom. Also, it was a long-established custom that the reigning king would marry a particular type of woman. However, this heir was attracted to the forbidden. Now, he is married with children and discovers her secret. This was a sure case of a family gone wild! Who are they? What have they become and why?