Diana's Deadly Affairs — How Princess Enraged Royals for Decades With Her Lust

Love-starved Princess Diana indulged her appetite for extramarital affairs during her unhappy union with the straying then-Prince of Wales – and palace handlers scrambled to hide the late beauty's flings to save the future King Charles from the embarrassment of having an unfaithful wife, courtiers have confided in OK!.

"There were so many cover-ups with Princess Diana. There are so many things that happened that the public doesn't know about," a royal insider said.

Photographer Denis O'Regan claims Kensington Palace pressured him to bury a photo he took of then 25-year-old Di at a David Bowie concert in 1987 – because she attended the rocker's show with her red-headed lover, Army Major James Hewitt.

O'Regan, Bowie's official photographer, recalls the People's Princess being "so sweet" as she asked if the "Modern Love" singer would want a picture with her.

But he says his backstage snapshot stirred up a hornet's nest when her royal minders got wind of it.

"The next day, my agent got a call from (the) palace, saying don't use the pictures because word had gone out about James Hewitt," O'Regan said.

Diana was involved with cavalry officer Hewitt, her riding instructor, from 1986 to 1992 – and tongues wagged among the high-society set about the hush-hush couple.

O'Regan explained to us the palace wanted to keep the photo under wraps because "they just didn't want Diana in the press."

He added, "It was really (that) they didn't want to fuel the James Hewitt fire. So the more pictures that weren't out there, the better, because someone would have said, ‘This is her at the show that she turned up to with James Hewitt,' even though I didn't get the multimillion-dollar shot of the two of them together because no one knew who he was."

Lady Diana Spencer was just 20 when she married 32-year-old Prince Charles in 1981 – but their fairy-tale wedding soon became a marital nightmare.

The princess promptly gave birth to an heir, Prince William, and a spare, Prince Harry, but her husband – now King Charles – had reignited his affair with longtime love Camilla Parker Bowles, who is his current queen.

Sources have revealed the crestfallen young bride had even tried to lure Charles away from Camilla with affectionate letters, but she failed to win his heart, which is why by the mid-1980s, Diana had also decided to play the field – and the palace feverishly worked to conceal her many infidelities.

"Charles was unfaithful to her, which is why she stepped out on their marriage," an insider said. "They didn't love each other."

As the relationship between Charles and Diana further crumbled, she engaged in a lengthy affair with Hewitt – until he was posted overseas and refused to cut short his career for her.

However, the dashing military man wasn't the only guy rumored to have caught the interest of the lonely princess. Barry Albert Mannakee was a police officer with the Royal Protection Squad who was assigned to Diana as a bodyguard in 1985 – shortly before her hookup with Hewitt – but sources say he was transferred a year later amid gossip that he was canoodling with his charge.

Before Diana's 1996 divorce from Charles – which occurred one year before her fatal car wreck in Paris – the princess was also said to have fallen for gin heir James Gilbey, art dealer Oliver Hoare, rugby star Will Carling, and heart and lung surgeon Hasnat Khan.

There were also rumors of a fling with rocker Bryan Adams. She shared a famously flirty dance with Saturday Night Fever stud John Travolta at a 1985 White House gala, and allegedly caught the wandering eye of Spain's King Juan Carlos I, who had a notorious past as a playboy prince.

As OK! previously reported, Ghislaine Maxwell – the jailed madam of convicted predator Jeffrey Epstein – recently revealed her dead financier boss was once set up on a date with Diana in 1991.

Diana's last suitor – 42-year-old playboy Dodi Fayed – died in the same 1997 accident that took her life.

"She used to collect men in the old-fashioned romantic way," a friend told Sally Bedell Smith, author of Diana in Search of Herself: Portrait of a Troubled Princess.

A source said: "She would give you a look with lowered eyes. You knew deep down it was a game she played, and a very clever one in a way, not cynical, but by doing this, she won everybody over."

Had Diana survived her 1997 Paris car smash, she would have toasted her 65th birthday this year.