Britain’s PRINCE WILLIAM  cheated on bride-to-be KATE MIDDLETON! And, palace insiders tell The ENQUIRER, heartbroken Kate now wants to call off their glittering wedding ceremony after a string of betrayals.

The final straw came when she was being briefed about royal marriage by Palace advisers, who told her William would have mistresses, and she had to "grin and bear it."

The 28-year-old prince has always loved beautiful women and, says one well-placed source: "Kate is troubled by the disrespectful behavior William has shown her over the last seven years."

The most hurtful and humiliating was this picture of his lip lock with the sexy British pop star Natasha Hamilton – at a time when Kate least expected it!

"Kate and Wills had just returned from a romantic vacation in the Caribbean four years ago, and a picture of Wills kissing Natasha was published in nearly every paper in Britain," says the source.

"All of Kate’s friends and family saw it. It was devastating for her!"

The kiss took place at a charity concert and caused a huge fight between Kate and William.

"He didn’t even try to be discreet," said the insider. "That’s what upset Kate most – she thought William was being blatantly disrespectful to her, and she’s still haunted by that photo today.

"And to make matters worse, Kate is now being warned by royal courtiers that she must be prepared for William to follow in his philandering father’s footsteps – and take a mistress," continued the insider.

"’It won’t be IF he does, my dear,’ Kate was told by one of Queen Elizabeth’s advisers. ‘It will be WHEN he does – and then you must simply turn a blind eye.’"

The pronouncement was like a knife in the heart for the 28-year-old princess-to-be, added the source.

"Kate’s been briefed on all matters of royal protocol – how she’s expected to behave in public, what to
wear, even when to smile and when to look serious," the insider divulged.

"But when she was informed that her future husband would undoubtedly cheat on her, she felt physically ill. Now she… doesn’t want to go ahead with the wedding!"

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