As The ENQUIRER first reported Jackie Kennedy had a steamy affair with JFK's brother Bobby but we've learned she also shut off his life support  — not his wife!

In the wake  of JFK's assassination in 1963 Jackie began a 4 year affair with his brother Bobby which was no secret to Kennedy insiders and that when RFK was gunned down it was Jackie and not his wife Ethel who told docs to pull the plug, the explosive tell-all Bobbie and Jackie: A Love Story revealed.

"I suspect Bobby would've liked to dump Ethel and marry Jackie, but, of course, that wasn't possible" the late Franklin D. Roosevelt, Jr. reveals in the C. David Heyman book. 

The reason being the Kennedys were staunch Catholics.

"It was the coming together of a man and a woman as a result of his bereavement and her mental suffering at the hands of her late, lecherous husband," Jackie confidant Truman Capote divulged.

By 1967, Jackie was also dating Greek tycoon Aristotle Onassis but decided to hold off on breaking up with Bobby until after his 1968 Presidential run.

But fate, in the hands of gunman Sirhan Sirhan, changed all that when on June 4, 1968 he shot Bobby at the Ambassador Hotel in Los Angeles minutes after Kennedy had won the California primary.

According to the book, Jackie jetted to his bedside and Ethel allowed her to stay with the rapidly fading RFK. Bobby was soon brain-dead but a distraught Ethyl refused to pull the plug and younger brother Teddy was in no shape.

On June 6, 1968, 1:20 AM, Jackie Kennedy took charge, ordering the doctors to shut down the respirator and signed the consent form.

Four months later she married Onassis.