Washington, Feb 18 (DPA) John F. Kennedy’s many love affairs included a relationship with the Swedish aristocrat Gunilla von Post that started right before his 1953 marriage to Jackie and ended more than two years later.

But until now, the 78-year-old von Post had kept under cover the passionate written evidence of her affair with the man who would become US president.

Now the assassinated president’s affectionate declarations of love in letters and telegrams are available to buyers in an online auction at legendaryauctions.com. The starting bid of $25,000 jumped to $42,500 the same day the auction opened Wednesday.

Gunilla von Post, the daughter of an upstanding Swedish family, waited until the 1994 death of Jack Kennedy’s widow, Jackie, to reveal all in her confessional book, “Love, Jack,” published in 1997.

Thirteen years later, she is offering through the Chicago-based auction house 11 hand-written letters and one telegram detailing how the playful 36-year-old US senator becomes more and more smitten with the 21-year-old blonde Swedish bombshell.

They met in August 1953 while vacationing on the French Riviera, a month before Kennedy’s wedding. They danced and shared a farewell kiss, von Post says in her book. All the while her heart went “boom boom boom boom”, she once told ABC News.

The young senator was similarly infatuated, and could not get her out of his mind. He tracked down her address and sent her a letter in March 1954, followed by another in June suggesting a possible meeting.

“I thought I might get a boat and sail around the Mediterranean for two weeks �with you as crew. What do you think? Best, Jack,” he wrote.

Gunilla warmed to the idea, writing in her book: “I longed to be close to him again, to feel that exciting intimacy that had been so intense (on the Riviera.) The boat, the blue water, the idea of Jack and me alone at sea was romantic beyond belief.

“I knew, however, that Jack had a wife and that I shouldn’t be having this dream. But every time I pushed this vision away, it crept back, invading my heart.”

Instead of sailing off into the sunset with Gunilla – whom he starts calling his “Swedish gorilla” and “my Swedish flicka” – Kennedy ended up in hospital with a serious, life-threatening back operation followed by months of recovery and more letters.

Finally, in August 1955, two years after their first enchanted Riviera meeting, the pair spent a week together on a Swedish beach – not Kennedy’s first choice, but the only one offered by Gunilla.

Later in the month, they tried to meet again in Europe, but he writes his lover to say he had just gotten word “that my wife and sister are coming here. It will be complicated.” He ends the letter: “All I have done is sit in the sun & look at the ocean & think of Gunilla … All love, Jack.”

After returning from Europe to Washington, Kennedy insists that Gunilla move to be near him, promises he will find her a job as a model and indicates he will discuss a divorce from Jackie with his father.

Gunilla recalls in her book Jack’s description of his father, Joseph Kennedy’s, irate reaction at the suggestion: “You’re out of your mind. You’re going to be president someday. This would ruin everything. Divorce is impossible.”

In the following weeks, Jackie became pregnant and miscarried. In July 1956, Gunilla married Anders Ekman. In November 1960, Kennedy was elected the first Catholic president to the US presidency. He was assassinated in 1963.