Prince Charles met Camilla Parker Bowles before Princess Diana, but he didn't marry the Duchess of Cornwall first for a reason.

The Prince of Wales and Camilla started dating even before he met the late Princess of Wales. However, their romance did not end up in marriage immediately. Instead, Camilla ended up marrying Andrew Parker Bowles, while Prince Charles tied the knot with Princess Diana. However, they eventually divorced their spouses to be together.

According to Sally Bedell Smith's biography "Prince Charles: The Passions and Paradoxes of an Improbable Life," there's a reason why Prince Charles didn't marry Camilla in the first place. The author claimed she was apparently perceived as an "experienced" woman which was a nonstarter for the royals in terms of their perspective for a suitable spouse for Prince Charles. Second, Camilla wasn't perceived as "aristocratic" enough for the next-in-line to the throne, Reader's Digest noted.

"Lovely for you two to have a fling, but this absolutely cannot end in marriage," Prince Charles' great uncle, Lord Mountbatten, reportedly advised the prince (via Express).

Soon after, the Prince of Wales was called away on naval business overseas. After being away from each other, Camilla reconnected with her former beau, Andrew. Later on, Prince Charles married Princess Diana.

When the former lovers reunited after they split with their partners, they struggled to please everyone including the Queen. In fact, according to Tom Bower's book "Rebel Prince: The Power, Passion and Defiance of Prince Charles," the monarch did not support Prince Charles and Camilla's affair. Queen Elizabeth II "actively disapproved" the Duchess of Cornwall even if both were already divorced.

When Prince Charles and Camilla eventually tied the knot, the Queen showed signs of displeasure. However, according to a body language expert, there are fewer distress signals during their union compared to that of Prince Charles and Princess Diana.

"Charles and Camilla's wedding was a more modest affair and there were fewer distress signals on display. Charles has finally married the woman he loves," Dr. Peter Collette said. "But the event is not without its tensions. When the couple emerges there appears to be some indecision about what is going to happen next. Then we see the Queen exposing her tongue."

"This is an unconscious gesture of rejection. It's what we do when we disapprove of something and want symbolically to push it away," the expert explained. "It's a feature the Queen is displeased – either about the arrangement or about the wedding itself."

Prince Charles and Camilla
Meghan Markle makes fashion faux-pas in Ireland - did YOU spot it?Why Prince Charles didn't marry Camilla Parker Bowles after they started dating? Pictured: Prince Charles, Camilla and Queen Elizabeth II watch the RAF flypast on the balcony of Buckingham Palace, as members of the Royal Family attend events to mark the centenary of the RAF on July 10, 2018 in London. Getty Images/Chris Jackson