John F. Kennedy and Marilyn Monroe’s Affair Was Reportedly the Only 1 That Bothered Jackie Kennedy Onassis

John F. Kennedy earned a reputation as a playboy right around the time that he became president. Then married to Jackie Kennedy Onasis, the former POTUS was said to have an insatiable sexual appetite. He reportedly was happy to indulge that appetite with a bevy of different beauties, all of which Kennedy Onasis knew about. According to experts, Kennedy Onasis was only ever threatened by Marilyn Monroe, one of JFK’s most mysterious paramours.

How many affairs did John F. Kennedy have?

Over the years, powerful men have been ousted as adulterers. That is no surprise, and has been pretty much accepted. JFK, however, has long been considered the most prolific of adulterers. Since his 1963 death, his affairs have been discussed openly. According to the New York Post, JFK himself wasn’t shy about his conquests. Reportedly he would tell anyone who would listen that he needed to have sex daily to feel satisfied, and his list of sexual partners is believed to be a long one.

John F. Kennedy and Jacqueline Bouvier sit together in the sunshine at Kennedy's family home at Hyannis Port, Massachusetts, a few months before their wedding.
John F. Kennedy and Jacqueline Bouvier | Bettmann/Getty Images

No one knows how many women he bedded over the years. Still, it is largely accepted that he slept with everyone from socialites to interns to entertainers and strippers during his 10-year marriage to Kennedy Onasis. Everyone from Angie Dickinson to Judith Campbell Exner is said to have slept with JFK. His most widely discussed affair was with Marilyn Monroe. Reportedly, it’s the one that bothered Kennedy Onasis the most.

JFK’s most salacious affair is still shrouded in mystery

 JFK’s most salacious affair is said to be the one that bothered Kennedy Onasis the most. Still, there is no real evidence that JFK and Monroe were embroiled in a longstanding affair. There is just a single photo that places Kennedy and Monroe in the same room, and Monroe herself never copped to having a longstanding relationship with the former president.

Marilyn Monroe seen talking to John F. Kennedy and Robert Kennedy in an undated photo
Marilyn Monroe with John F. Kennedy and Robert Kennedy | Cecil Stoughton/The LIFE Images Collection via Getty Images/Getty Images

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Experts are still divided on the affair’s seriousness, although most seem to agree that a sexual encounter of some kind did happen. One biographer, Donald Spoto, believes that Monroe and JFK hooked up at least once but may have met up as many as four times. Other biographers suggest the affair was a bit more involved but hardly threatened JFK’s marriage. Still, it’s argued that Monroe’s presence unnerved Kennedy Onasis.

Jackie Kennedy Onasis reportedly worried that Monroe would go public

Kennedy Onasis was fully aware of JFK’s wandering eye. According to several sources, she mostly dealt with the affairs quietly, and none of them deeply concerned her because she never worried that JFK was going to leave her for one of his conquests. After all, it wouldn’t look good. According to biographer Charles Casillo, Kennedy Onasis did feel threatened by Monroe, but not for the reasons one would think.

 Marilyn Monroe poses for a portrait laying on the grass in 1954 in Palm Springs, California
Marilyn Monroe poses | Baron/Hulton Archive/Getty Images

In his book, Marilyn Monroe: The Private Life of a Public Icon, Casillo explained that Kennedy Onasis viewed Monroe as a loose cannon. In short, she didn’t think Monroe lived by the societal rules that everyone else did. Reportedly, Monroe was the only affair partner who dared to approach Kennedy Onasis directly. Casillo argues that Kennedy Onasis feared that Monroe would go public with the affair, bringing scandal and shame to the Kennedy family.