The US tabloid adds that Camilla's previous blowouts with the Royal Family were partly to blame for the new split.
"The royals are convinced Camilla is nuts!" a source says.
The insider adds, "She's been fighting the entire family."
Camilla, since announcing her shock decision, has been on a "warpath", GLOBE adds.
"She's threatened to reveal all the royal family's darkest secrets," and has reportedly demanded a $400 million payout.
"There are frantic talks going on behind closed doors at Buckingham Palace, trying to negotiate some sort of face-saving compromise."
"But, you know Camilla will play hardball.
"There's nothing worse than a wannabe queen scorned, and the royals are bracing for one of the nastiest - and most expensive - royal bust ups in history."
The Royal Family is yet to respond to GLOBE's claims.