JFK Was with His Mistress When Jackie Gave Birth, Friend Carly Simon Says

The late Jacqueline Kennedy Onassis revealed to her close friend Carly Simon that not only was she aware of husband John F. Kennedy‘s marital indiscretions, she was “unbothered” by them, Simon writes in new memoir Touched by the Sun: My Friendship with Jackie.

The singer told NBC News in a candid interview this week that Onassis brought up sensitive topics involving both of her late husbands, President Kennedy and shipping magnate Aristotle Onassis, who both cheated on the the former first lady, Simon said.

“She learned the fact that it didn’t necessarily mean anything more than ‘wham bam thank you ma’am,’ ” Simon told NBC News’ Cynthia McFadden, referring to Jackie sharing her reaction to Aristotle cheating on her with opera singer Maria Callas.

In the book, Simon details how Jackie dealt with President Kennedy’s notorious wandering eye.

“‘She was similarly unbothered by Jack’s affairs,’ ” McFadden said in her interview with Simon, quoting from the memoir. “‘In a cheerful but resigned way she told me that of course she knew about them. She just didn’t mind their presence as much as she might have, because she knew he [Kennedy] loved her much, much more than any of his dalliances.’ “

Simon told McFadden what did bother her friend, however.

RELATED: Carly Simon Opens Up on Unlikely Friendship with Jackie Kennedy — and Jackie’s Thoughts on JFK, Aristotle Onassis & More

Carly Simon (left) and Jacqueline Kennedy Onassis | Stephen Rose/Getty
Carly Simon (left) and Jacqueline Kennedy Onassis | Stephen Rose/Getty
Jacqueline Kennedy Onassis (left) with Carly Simon at a Labor Day party
Jacqueline Kennedy Onassis (left) with Carly Simon at a Labor Day party

“I think that some of the things had more effect on her,” Simon said, adding, “For instance, his not being there for the birth of a child, his being off with a mistress while she was in the hospital. There are various things that he did that by comparison must have hurt more.”

Simon was likely referring to 1956, when Jackie gave birth to a stillborn child while her husband was on a yacht with his mistress in the Mediterranean Sea “reluctant to return home quickly to his devastated wife,” according to The Washington Post. “With his cool detachment, he saw no reason to rush back — the baby was already lost.”

RELATED: Jackie Kennedy Onassis’ Luxurious Martha’s Vineyard Estate Is on the Market for $65 Million

In an exclusive interview with PEOPLE, Simon opened up about many facets of her unlikely friendship with Jackie, and how the “You’re So Vain” singer was at Jackie’s bedside as she lay dying at home in 1994.

“I was holding her hand, telling her I loved her and saying goodbye,” Simon, 74, her voice quavering, told PEOPLE. “There was an otherworldly recording of monks singing, intermingled with sounds of uproarious laughter from the next room, where various Kennedys were having an Irish gathering. It was surreal.”

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