JOHN TRAVOLTA’s former boyfriend plans to release a bombshell tell-all that will rip the lid off their six-year gay relationship – and TheENQUIRER has a sizzling sneak preview of their steamy secrets.

In an exclusive interview, Doug Gotterba has told The ENQUIRER that the “Grease” star had an enormous sexual appetite, a desire for threesomes, a hunger for kinky porn – and a genius for hiding his sexual double life!

The two men first met in Feb. 1981 – a year after Travolta starred in the hit movie “Urban Cowboy” – when the then 27-year-old star interviewed Doug for a pilot job.

Travolta hired Doug, who’d heard rumors the actor was gay, and on Sept. 21, 1981, he got proof. They became lovers.

“I know the date because I still have the log book and records,” Doug revealed, in a steamy tell-all.

“We flew into Monterey, Calif., and went up to the Highlands resort in Carmel. We had a wonderful dinner with a bottle of Merlot, and I got the sense I was being courted.”

In a hotel room that night, Doug said Travolta offered to massage him – “and it turned into something else!”

Recalling their first sexual encounter, the pilot, who was 31 at the time, said: “John was gentle, but very passionate. The next day, he told me, with a big smile on his face, ‘I really enjoyed last night.’ And I told him, ‘So did I.’”

After that, Doug said the two men became a gay couple, and working as Travolta’s pilot afforded him the perfect cover.

In the following years, they traveled to distant places, including Hawaii and Africa.

“I’d stay in the room next to John in luxury hotels,” said Doug. “Sometimes he’d bring women along as beards. But he would ask me to join him in his suite and we’d spend the nights together. It was our little secret.”

On some occasions, Travolta, now 60, made it clear he wanted another partner to join in their sex romps, according to the pilot.

“John talked one friend into getting naked and taking a shower with us. He also tried to get me to make a sex tape with him. But I refused.

“John was oversexed, and I knew that he had many other lovers on the side. Some of them I’d hear about – others he told me about himself.”

Travolta also was into a special kind of gay porn, divulged his bosom buddy.

“He had a stash of videos and magazines that he kept hidden in his bedroom. He also liked ‘Colt Video’ guys – real macho men with mustaches and Levi’s.”

Eventually Travolta’s sexual demands grew too great for his friend and their relationship ended in 1986. “John demanded that I come to his house at all hours of the day and night,” recalled Doug.

In 1987, Travolta met his future wife – actress Kelly Preston, now 51. A year after the couple wed in 1991, Doug said he ran into the “Pulp Fiction” star.

“We were making small talk when I blurted out, ‘So, John, tell me. Now that you’re married, do you still prefer men – or women?’

“He looked me straight in the eye and said, ‘Well, Doug, I still prefer men!’ I said, ‘Okay.’ And that’s
the last time we saw each other.

“I feel sorry for Kelly. She’s a lovely person. She’s in the middle of all this, and it’s unfair to her.”

Although a rep for the couple insists there is no trouble in the marriage, sources say $220 million is at stake in a potential divorce.