I can't think to any royal couple whose eldest child was born 10 or more years after the wedding; however, the late Duke and Duchess of Gloucester had their eldest son William 6 years after their wedding (wedding on 6 November 1935, birth of Prince William on 18 December 1941).
There were some royal couples childless; i.e. King Baudouin and Queen Fabiola of the Belgians, King Gustaf VI Adolf and Queen Louise of Sweden, King George II and Queen Elisabeth of Greece, the Duke and Duchess of Windsor, Prince Ludwig and Princess Margaret of Hesse-Darmstadt.