Article continues below advertisementOK! can reveal Kate Middleton and Prince William felt a "massive" sense of relief as plans for a quiet family Christmas appeared secure, after it was confirmed the Duke and Duchess of Sussex would not be visiting the U.K. for Christmas.The Prince and Princess of Wales, both 43, spent part of the festive season on the Sandringham estate with King Charles, 77, and Queen Camilla, 78, continuing a long-standing royal tradition.