King Charles reportedly shared heartfelt marriage advice with his eldest son, Prince William, according to royal author Ingrid Seward.

The 76-year-old monarch, who has been married to Queen Camilla since 2005, reflected on his own complex relationship history to offer guidance.

“[His father] said, ‘Look, William, there’s nothing more important than your family,’” Seward shared with Fox News. “‘Don’t make the mistakes that I made. I just did duty, duty, duty. I neglected my marriage, and look what happened.’”

Charles and Camilla first crossed paths at a polo match in 1970 and formed a close bond. However, their budding romance was interrupted when Charles served an eight-month stint in the Royal Navy. During this time apart, Camilla married her longtime boyfriend, Andrew Parker Bowles, in 1973.

With Camilla married, Charles wed Lady Diana Spencer in 1981, marking the beginning of a marriage that was later marred by public scandals and his infidelity. Camilla divorced Parker Bowles in 1995, and Charles and Diana’s marriage officially ended the following year. Tragically, Diana died in a car crash in 1997 at the age of 36.

Prince William, meanwhile, met Kate Middleton in 2001 while studying at St. Andrews University in Scotland. Their relationship blossomed as they lived together with friends and eventually as a couple. By 2004, their romance was public knowledge, though the pair briefly split in 2007 after nearly five years of dating.

Later that year, they reconciled, and William proposed in 2010. The couple married in 2011 and have since welcomed three children: Prince George, Princess Charlotte, and Prince Louis.

Seward noted that King Charles has always been a strong supporter of William and Kate’s relationship, particularly urging his son to prioritize family. This encouragement became even more significant after Princess Catherine, 42, publicly revealed her cancer diagnosis in March, following the king’s own cancer announcement in February.

The Princess of Wales has since declared herself cancer-free, with Seward emphasizing Charles’ belief in the importance of family time over rigid adherence to royal duties.