Prince William and King Charles might have different approaches to royal life, but there’s one sweet thing they share in common. King Charles has been married to Queen Camilla for 21 years, while the Prince and Princess of Wales celebrated their 15th anniversary this year. But although their marriages might be quite different, The Queen and Princess Kate have the same influence on their husbands in a way that Princess Diana didn't.

"William definitely visibly relaxes when Catherine is near, and you see a similar thing with Charles and Camilla, actually," Simon Vigar, author of The Four Wives of Windsor , told Hello!…