He is married to HRH Princess Friederike Luise Thyra Viktoria Margarete Sophie Olga Cecile Isabelle Christa of Hannover, Princess of Great Britian and Ireland and of Brunswick.
They got married on January 9, 1938 at Athens, Kingdom of Greece, he was 26 years old.
Child(ren):
http://trees.ancestry.com/pt/AMTCitationRedir.aspx?tid=158940490&pid=4543/ Ancestry.com