In her 2011 book, The Making of a Royal Romance: William, Kate, and Harry, author and royals insider Katie Nicholl drops a bombshell of a story. It turns out that Prince William once basically wrecked Christmas with Kate when he changed their plans at the very last minute.
The story goes something like this: the pair were meant to spend the Christmas of 2006 with Kate Middleton’s family. Sometime the night before Christmas, Prince William “had a change of heart” and decided they would spend the holiday with his family instead. This was years before their 2011 wedding, and Katie Nicholl says that Kate was upset about the change in plans and worried this was a bad sign for her relationship.
Katie explains, “She had good reason to be concerned. William had been having second thoughts and sat down with his father and grandmother to have a frank discussion about his future with Kate. Both advised him not to hurry into anything.”
Kate Middleton ended up in tears during the holiday, likely from a combination of missing her family and being worried.
Source : https://www.littlethings.com/prince-william-kate-cry/