Prince Charles and Princess Diana
Prince Charles and Princess Diana are pictured at an official event during their first royal Australian tour 1983 in Newcastle, Australia. Patrick Riviere/Getty Images

Prince Charles was previously accused of not caring toward Princess Diana. But the truth was that he actually cared deeply for his ex-wife.

According to royal author Penny Junor, the heir to the throne’s behavior toward the late royal changed after he realized how unpredictable Princess Diana was. Since then, Prince Charles “hardened” and became “callous” toward the mother of his two sons.

Despite the changes that he saw in himself, Prince Charles still tried his best to help Princess Diana. He found a top psychiatrist that could help her out. Prince Charles also went as far as distancing himself from his friends just to appease the Princess of Wales.

“He had cut out of his life the friends she disliked or of whom she was suspicious; good, loyal friends, some of them friends since childhood – and, in typical style, he took the easy way out and did it without telling them. They were left to wonder what had happened when phone calls, letters and invitations to Highgrove and Balmoral simply stopped,” Junor wrote in “The Firm.”

Princess Diana also reportedly disliked Prince Charles’ dog, Harvey, because he was smelly. But at the end of the day, none of Prince Charles’ efforts made any difference in his relationship with Princess Diana. After seeing Princess Diana’s outbursts and tantrums, the future King felt helpless so he gave up.

“When she made dramatic gestures he walked away, when she self-harmed he walked away. Not because he didn’t care but because he couldn’t help… He felt desperate, hopeless and guilty, and to this day he feels a terrible sense of failure for not having been able to make his marriage work,” Junor said.

And in 1992, after the couple traveled to Korea for their royal engagement, their marriage broke down for good. And any hope that the royal couple could stay friends also went down the drain. On Dec. 9, the couple’s separation was announced.