Prince William and the Princess of Wales are set to mark a special occasion “very differently” after Kate’s cancer diagnosis. The royal couple will celebrate their 13th wedding anniversary on April 29. However, a royal commentator said the Waleses will not celebrate the same way as usual due to Kate’s health. Richard Fitzwilliams said: “They will undoubtedly be celebrating their 13th wedding anniversary privately. “This year will be very different from previous years as Catherine is undergoing preventative chemotherapy after recovering from abdominal surgery.” Prince William married his longti…