After his grandfather, George I., became king of Great Britain and Ireland in 1714, Frederick was known as duke of Gloucester and made a knight of the Garter, having previously been betrothed to Wilhelmina Sophia Dorothea (1709-1758), daughter of Frederick William I., king of Prussia, and sister of Frederick the Great.
In that year Wagner married Wilhelmina Planer, an actress at the theatre at Konigsberg.
In 1791 he married Frederica Wilhelmina, daughter of Frederick William II., king of Prussia, thus cementing very closely the relations between the houses of Orange-Nassau and Hohenzollern.
Having been left a widower on the 3rd of June 1877, he married on the 7th of January 1879 Adelheid Emma Wilhelmina Theresia, second daughter of Prince George Victor of Waldeck-Pyrmont, born on the 2nd of August 1858, and Wilhelmina was the only issue of that union.
On the 7th of February 1901 Queen Wilhelmina married Henry Wladimir Albert Ernst, duke of Mecklenburg-Schwerin (born on the 19th of April 1876).