Camilla Parker Bowles and Prince Charles
Camilla Parker Bowles has a certain trait that attracts Prince Charles. Pictured: Prince Charles and Camilla continue to laugh after a bubble bee took a liking to Prince Charles during their visit to the Orokonui Ecosanctuary on Nov. 5, 2015 in Dunedin, New Zealand. Getty Images/Rob Jefferies

Camilla Parker Bowles and Prince Charles' romance has stood the test of time because she knows how to keep her man happy, according to one source.

The Prince of Wales and Duchess of Cornwall briefly dated before they married their ex-spouses, Princess Diana and Andrew Parker Bowles, respectively. Their marriages ended up in divorce, so they rekindled their romance.

According to Francesca Specter, a journalist for Express, Camilla has a certain trait that attracts Prince Charles. She "kind of jollies" the future king.

Former press secretary Charles Anson had spent some time with the couple. According to him, Camilla is good at helping the royal ease his burden. "She doesn't let him get too overburdened by the woes of the world," Anson said.

Although Prince Charles dated Camilla prior to the late Princess of Wales, he reportedly did not marry her at that time because his family was against her. The royal family found Camilla an "experienced" woman which is a nonstarter for the family in terms of a suitable spouse for Prince Charles. In addition, Camilla was apparently not "aristocratic" enough for the future king.

Even Prince Charles' great-uncle advised him against marrying Camilla. "Lovely for you two to have a fling, but this absolutely cannot end in marriage," Lord Mountbatten told the Prince of Wales when he was still dating Camilla.

In related news, Camilla was present when Prince Charles and Princess Diana exchanged "I do's." The bride was aware that her husband's ex was there. In fact, Princess Diana opened up about this in her royal biography with Andrew Morton.

"I knew she was in there, of course. I looked for her," Princess Diana said. "So walking down the aisle, I spotted Camilla, pale gray, veiled pillbox hat, saw it all, her son Tom standing on a chair. To this day you know — vivid memory."

Camilla was reportedly invited at the event because her husband has a had a significant role in the wedding procession. Andrew was the commanding officer of the Household Cavalry Mounted Regiment. So, he would oversee the ceremonial escort that accompanied the couple's carriage ride.

In addition, Prince Charles and Camilla had been friends for a decade. Their friendship remains even after they split.