Ethel Kennedy knew husband Robert was a serial cheat who had affairs with actresses Kim Novak and Lee Remick – AND sister-in-law Jackie

Ethel Kennedy, who died Thursday at the age of 96, lived a life of tragedy, made painful by her knowledge of her husband’s many affairs.

But she tolerated Bobby’s deception because she knew from the start that there was “no tradition of monogamy in the Kennedy clan.”

Bobby’s widow understood the Kennedys better than anyone who wasn’t born into the family and was fully aware of what she was getting into.

She knew that infidelity was the price she had to pay for her marriage to a Kennedy man and that she had to keep quiet because of an unspoken contract.

Ethel even turned a blind eye to rumors that her husband was sleeping with his sister-in-law Jackie Kennedy.

She admitted that the close friendship between the two may not have been entirely a bad thing for her husband and that perhaps it was Jackie who finally rescued Bobby from his deep despair after Jack’s murder in 1963.

The details of Ethel’s unwavering support for her husband were best described in Larry Tye’s 2016 book “Bobby Kennedy: The Making of A Liberal Icon.”

The book said that Ethel ‘loved her husband more completely than she thought possible’ – and this meant she could look the other way.

Bobby was seen as the most puritanical of his eight siblings and was the one asked by his brother to become attorney general when he became president.

Bobby’s tough, unapologetic political style was like that of their wealthy father Joseph Kennedy

And according to Tye, he also learned his wandering eye from his father, as Joe had a mistress, silent film star Gloria Swanson, and had affairs with numerous other women.

Tye wrote that Joe passed on the idea to his sons that “when it came to sexual mores, boys play while girls pray.”

Bobby’s first sexual experience was at age 21 in a whorehouse in Harlem, New York, after his father paid him to have sex with a black woman. Bobby’s assessment afterwards was that it was ‘not bad, but not great either’.

He married Ethel in 1950, when she was 22, and the following year Kathleen, the first of their eleven children, was born. The youngest, Rory, was not born when her father was shot in a Los Angeles hotel.

But outside of his marriage, Bobby’s list of conquests would also include stars like Kim Novak, Lee Remick and the singer Claudine Longet.

He is also said to have had an affair with Marilyn Monroe – possibly at the same time as his brother.

Tye interviewed Ethel, then in her late 80s, extensively for the book and gave one of the most candid accounts yet of her late husband’s feuds.

The book said: ‘Ethel has lived with the rumors for fifty years and she says she has not listened to or read them for a long time.

‘She tried to shut them out then too, even though they must have hurt.

‘She never raised any suspicions.

“She also understood Bobby’s family better than anyone who wasn’t born into it, and she knew what her church and theirs also said about sex outside of marriage: there was no tradition of monogamy in the Kennedy clan.

‘She loved her husband more than she thought possible and still does.

“And she knew he always came home, not just to the kids, but to her too.”

Richard Goodwin, a friend of Bobby’s who traveled extensively with him, was more blunt, saying it was a “Kennedy family tradition” to sleep around, although Bobby was “much more selective and limited” than his brother Jack.

FBI files alleged that Bobby and Jackie, who died in 1994, slept together from 1964 until he was murdered in 1968.

Their relationship would be based on their shared grief and on a long-standing affection between the two.

According to Tye, on the night of Jack’s funeral, Bobby asked her, “Shall we go visit our friend?” and the two knelt by his gravestone in silent prayer.

Tye writes, “They had been good friends before, but not close confidantes like this.

“Although Ethel had always had problems with Jackie, they had not had any jealousy until now.”

FBI files revealed that Ethel was so concerned about the alleged affair that at one point she confronted David Ormsby-Gore, the British ambassador to the United States during the Kennedy administration, and asked what he knew about the relationship.

But what is clear is that they were both “devastated by their loss and each determined to help the other through it.”

When JFK was shot, Bobby made a point of going there Andrews Air Force Base to meet Jackie and his brother’s body.

Even though the entire nation was in mourning, “no one, not even Jackie, would grieve as deeply or as long as Bobby,” Tye wrote.

The book said: ‘The two were closer than any brothers had been at high levels of government, speaking in a private code, constantly interrupting each other and finishing each other’s sentences.

‘Gone now were the dreams about what they could achieve together.

“The sniper’s bullet that entered Jack’s skull shattered Bobby’s own vision, while also breaking his heart.”

Bobby’s murder was just one of a series of tragedies that befell Ethel during her lifetime.

Her parents died in a plane crash in 1955, and her brother George died the same way ten years later, two months before his widow suffocated.

Two of her sons predeceased her: David succumbed to a drug overdose in 1984 and Michael in a skiing accident on New Year’s Eve 1997.

Scandal also surrounded her family. Son Joe was in a car accident that left a passenger paralyzed. Bobby Jr. – who split with most of the family over his support of Donald Trump – was arrested for heroin possession and before his death, Michael entered sex addiction therapy in Maryland after it was discovered he was having an affair with his babysitter that began when she was still was only 14.