JFK and His Grave Designer Dated Same Woman at Same Time, While Late President Was Married to Jackie

John F. Kennedy‘s love life is as much a part of his legacy as his political achievements. Now, a new chapter has been written in an upcoming memoir that claims JFK and the man who designed his grave were once dating the same woman at the same time.

Jack Warnecke, who died at 91 in 2010, breaks it all down in the upcoming memoir, Camelot’s Architect: The Untold Story of Jackie Kennedy, Lafayette Square, and a Secret Romance, in an excerpt shared by People on Friday, November 6. The book is set for release on November 10.

The famed architect first met JFK in 1956 through a mutual friend, with the two men bonding over their shared love of architecture, preservation and beautiful women, according to People. After Kennedy ascended to the presidency, the magazine stated Warnecke was invited into their inner circle, where he met Jackie Kennedy.

In early 1963, Warnecke was asked to help review sites for the proposed JFK Library in Boston, per People. It was during a trip back on Air Force One, according to Warnecke’s book, that JFK asked him about a young woman Warnecke was dating at the time.

Warnecke wrote that he had invited the unnamed woman for a weeklong vacation in the Caribbean around that time. But after his return to Washington, D.C., “She told me something had happened while I was away and, as a result, she could no longer take the trip.”

During a subsequent dinner, Warnecke found out why.

“About halfway through the meal, she felt she couldn’t put it off any longer,” he wrote. “The reason, she admitted, was the president had entered into her life.”

“She was now romantically involved with Jack and felt she could no longer go on the trip with me,” he continued. “I couldn’t believe what I was hearing, especially after my recent discussion with the president about her.”

“I told myself this is the leader of the free world,” he went on to lament. “What could I do?”

He claimed in the book that the woman would often see the president on the weekends, while Jackie and their children, Caroline and John, were in Virginia.

After JFK’s assassination on November 22, 1963, Jackie and the late president’s brother, Robert F. Kennedy, asked Warnecke to design the president’s gravesite at Arlington National Cemetery. In that following year, per People, Warnecke and Jackie fell deeply in love and remained close until her 1994 death.

Warnecke’s daughter, Margo Warnecke Merck, who oversees her father’s archives, told People that he never spoke about the woman he and JFK both dated, nor does she know if he ever told Jackie. She only learned about it, she said, after her father’s death.