Prince Charles and Princess Diana
Prince Charles wanted to call off his wedding to Princess Diana after realizing that they were incompatible. Pictured: Prince Charles and Princess Diana at Westminster Abbey, London, for a centenary service for the Royal College Of Music on Feb. 28, 1982. Getty Images/Fox Photos

Prince Charles and Princess Diana knew that their marriage was doomed.

Robert Jobson's new biography that marks Prince Charles' 70th birthday in November has shocking revelations about the Prince and late Princess of Wales' marriage. According to the veteran royal reporter, the future king felt that he and Princess Diana was incompatible and wanted to call off their wedding.

Years after Prince Charles and Princess Diana's fairytale wedding, he reportedly confided to a friend about his sentiments in the run-up of their nuptials.

"I desperately wanted to get out of the wedding in 1981, when during the engagement I discovered just how awful the prospects were, having had no chance whatsoever to get to know Diana beforehand," Prince Charles admitted.

Prince Charles realized this when he talked to Princess Diana about his work commitments and what kind of day he had and she would only stare at him blankly.

"She seemed incapable of grasping the intellectual thread of what he was saying," Jobson wrote.

In addition, Princess Diana had "alarming and irrational mood swings and temper, which the prince found impossible to deal with."

"The more he saw of his volatile fiancee, the more Charles knew in his heart that he'd made a terrible mistake," the author continued.

According to Princess Diana, they only met 12 times and barely know each other when they got married. Part of the reason they decided to get married quickly was that Prince Charles was already 32 when they started dating and there was a pressure mounting on the heir to find a suitable wife.

However, Prince Charles has always been in love with Camilla Parker Bowles. The royal family didn't approve the latter because they found her "experienced" and not "aristocratic" enough for the future king.

"It was absolutely vital to have on the throne somebody who was a virgin," Dr. Piers Brendan said to clarify Camilla's "experience." "A future Queen must have no past."

However, Prince Charles never got over Camilla. For Penny Junor, his relationship with Camilla was like no other.

"I think he had a closer relationship to Camilla than practically anybody. He really really loved her," Junor said. "They had so much in common their brains kind of worked in the same way. I guess he didn't meet anyone else who quite matched up to her."

Princess Diana felt this and said in one interview that their relationship didn't work because "there were three of us in this marriage, so it was a bit crowded," implying about Prince Charles and Camilla's affair.