JFK Jr almost killed his ex-girlfriend in a horrific kayaking accident

John F. Kennedy Jr. nearly killed his first serious girlfriend, 13 years before he crashed the flight that killed him and his wife Carolyn Bessette, a new book reveals.

'Ask Not: The Kennedys and the Women They Destroyed', by DailyMail.com columnist and author Maureen Callahan, tells how JFK Jr. had a habit of putting others in danger.

'He had a death wish — not only for himself, but the women in his life. He had more near-misses in his teens and twenties than the public knew,' Callahan writes. 'Speeding, swimming too far out into the ocean, driving recklessly onto pavements or while high on pot, skiing in white-out conditions.'

He also nearly 'killed' his first serious girlfriend, Christina Haag, 'more than once', Callahan says.

In 1986, the pair were on vacation in Jamaica when JFK Jr. insisted they go kayaking in the open sea without life jackets.

'Nothing to be afraid of,' he reportedly told Christina.

However, the couple soon 'found themselves helpless', with strong currents pushing them towards a giant boulder. Had it not been for a rogue wave lifting them over it at the last moment and to safety, they could have died.

After crash-landing on a remote beach, JFK Jr. 'went into a trance', Callahan writes — adding that Christina later recalled that 'dying, getting that close to it, seemed a high for him'.

Despite her refusal to get back in the kayak — and offers from a group of local fisherman to take them to the mainland the following morning — John again insisted, saying they would kayak back that night, Callahan reveals.

But on this return journey the conditions were even worse, with the pair soon finding themselves '15ft underwater'.

Years later, Christina was reportedly still unable to remember how they'd survived.