JOHN TRAVOLTA‘s gay cheating scandal has sparked a new uproar – and pals fear it may send his pregnant wife KELLY PRESTON into premature labor!

After The ENQUIRER previously reported in our print edition a new book will reveal Travolta betrayed his wife by having gay sex in Hollywood health spas, its author alleges SIX MORE men have come forward to claim they were intimate with the Pulp Fiction star.

And with Kelly due to give birth to a boy in November, the turmoil has turned the 47-year-old actress into a bundle of nerves, sources say.

As The ENQUIRER  revealed in a blockbuster world exclusive, interior designer Robert Randolph has written a memoir that claims he witnessed Travolta, 56, regularly engaging in gay sex in Los Angeles steam rooms and names other celebrities who also used the premises to pick up male lovers.

Randolph says that since then he’s been inundated with e-mails from other men who claim to have been sexually intimate with the "Hairspray" star.

Now he plans to write a sequel to his book, "You’ll Never Spa in This Town Again," that will focus solely on Travolta’s alleged secret gay life.

"I have no doubt John Travolta is a sex addict. I’ve heard from many men who have either had gay sex with John or saw him having gay sex in health spas, steam rooms, locker rooms, you name it," Randolph, who’s gay, told The ENQUIRER.

"I’ve gotten so many e-mails that I’m writing a second book titled Tracking Travolta, and I’ve got plenty of material." He says he believes that eventually as many as 50 men may come forward who have either had sex with the star, or eyewitnessed him having gay sex.

While writing his first book, Randolph says he was attacked by thugs on the street and suffered a head injury. But he says his doctors say he’s now completely recovered.

Due to the avalanche of e-mails sent to his website, Randolph is moving the release date of his memoir up to December.

Despite his startling claims, Randolph – who passed an independently administered polygraph test about seeing the Grease star have sex with men – insists he has nothing against Travolta.

"I feel it’s my duty to expose John because he’s a hypocrite."