Inside Marilyn Monroe & JFK’s affair before star began romance with president’s brother ‘to get back at him,’ pal claims

MARILYN Monroe may have begun a romance with John F. Kennedy’s brother after their affair ended “to get back” at the president, a pal has shockingly claimed decades after her death.

Frank Sinatra’s longtime friend, Tony Oppedisano, made the bombshell claim about Marilyn’s relationships in his recently released memoir, Sinatra and Me: In The Wee Small Hours.

Marilyn Monroe famously sang Happy Birthday to JFK just months before her deathAP:Associated Press

Robert Kennedy (left) and John F. Kennedy (right) are said to have both engaged with MonroeGetty Images – Getty

Marilyn Monroe famously sang “Happy Birthday” to President John F. Kennedy (left)

Oppedisano credits years of conversations with Sinatra for the new glimpse at the trio’s dynamics.

As far as Monroe and JFK were concerned, Oppesidano wrote, “It was obviously a sexual thing, and I would expect that there were feelings on her side.”

Monroe famously sang “Happy Birthday” to JFK at a celebration of his 45th birthday in May 1962 – just months before her untimely death.

“It’s not like she was in love with” JFK, but rather that she “looked up to him,” he wrote. “She respected him; she admired him.”

“She loved what he was doing with the country, and then to have a physical relationship with him, she found him attractive and vice versa.”

But Monroe wouldn’t break up JFK’s marriage to Jacqueline Kennedy, regardless of how she felt about the president.

“Frank did say she had a sense of ethics and morals as well that she tried her best to live up to,” Oppedisano wrote.

There are differing accounts of how Monroe’s relationship with JFK’s younger brother, Bobby [Robert] Kennedy began.

Oppedisano claims Monroe may have begun seeing Bobby, to get back at the then-President.

“According to Frank again, she felt a little bit betrayed and, yet again, taken advantage of when it ended” with JFK, Oppedisano says.

“And to an extent, maybe her taking up with Bobby was to get back at him, and it wasn’t so much about Bobby as maybe sticking her thumb in JFK’s eye – ‘You’re not going to be with me, so maybe I’ll take up with your brother.’ “

Oppedisano also notes that Bobby Kennedy “was a different mentality all together.”

He also mentions that Bobby wanted to “impress on [Monroe] that he was as important as his brother,” claiming he would “tell her things that he shouldn’t have told her, sensitive information.”

In Monroe’s final days, Oppedisano claims Bobby felt she was “unraveling.”

Her August 1962 death was ruled a “probable suicide.”

Oppedisano claims Sinatra believed Monroe was killed.

“And he never got over it,” Oppedisano wrote.

Sinatra and Monroe, while good friends and confidantes, were never intimate, Oppedisano claims.

Oppedisano says she was “more than willing,” but Sinatra felt as though too many men took advantage of the bombshell.

“He told me he badly wanted to, that he was terribly attracted to her, but he always stopped short,” Oppedisano wrote.

“Marilyn was more than willing but Frank felt she was too troubled, too fragile for him to sleep with and walk away.

“He just couldn’t get rid of the feeling that sex with her would be taking advantage of a woman who’d already been used by so many men.”

Oppedisano says Sinatra believed Monroe was “beautiful, funny and charismatic.”

Monroe was married three times in her life: to James Dougherty, baseball player Joe DiMaggio, and playwright Arthur Miller.

She and Miller divorced in 1961, just months before she would die.