JOHN TRAVOLTA and his wife KELLY PRESTON are headed toward a $220 million divorce!

That’s what pals of the couple are tell­ing The ENQUIRER, and sources say that humiliated Kelly told her hubby of 21 years that they’re through for good unless he becomes more supportive of her career.

“Kelly has had it up to here with John,” confided a source close to the couple. “She’s tired of always having to take care of their family while he goes off gallivanting around the globe, for work or pleasure. Now it’s her time.”

But it didn’t look that way when John took a booze-filled train trip from Texas to California with an obsessed male fan, then went on a solo drive around L.A. before heading to New York and Or­lando to promote pricey watches.

The couple’s latest problem began in mid-March when Kelly got an opportunity to star in the pilot of a new sitcom called “Keep Calm and Karey On” in L.A.

“John completely poohed-poohed it,” SAID THE source. “He wanted her to stay put in Florida and take care of their kids.”

Kelly, 50, had put her career on hold after the couple’s 16-year-old son Jett tragically died in January 2009, and then she got pregnant with their son Benjamin, now 2. They also have daughter Ella, who is 13.

“Kelly and John had a knock-down, drag-out fight at their Florida home that ended with her stalking off and going to Los Angeles,” said the source. “And she told John that unless he changed his tune and started to carry more of the weight in the marriage, she’d see him in divorce court.”

There is a lot at stake as Travolta’s vast fortune includes expensive planes, vintage cars and pricey homes on both coasts.

Travolta’s lack of support for Kelly’s career is a real blow to her, say sources, since she’s stood staunch­ly by him as he was hit with a string of lurid gay scandals. In May 2012, two male masseurs filed sexual battery suits against the “Saturday Night Fever” star in federal court.

Although Travolta’s attorney vehemently denied the claims, several more men have come forward with similar accusa­tions against him.

And in June 2012, The ENQUIRER revealed Travolta had carried on a six-year affair with his pilot, Doug Gotterba.

“Kelly supported John during his tribulations these past few years, and she was champing at the bit to start acting again,” said the source.

“After all that John has put her through, he should have been in Los Angeles at Kelly’s side.”

Instead, The ENQUIRER has learned that the 59-year-old screen idol high-tailed it to Texas and hopped an AMTRAK train at 3 a.m. on March 21 from San Antonio to L.A. with a 42-year-old hunk.

“When John saw that his friend was in a different car, he wasn’t happy,” an eyewitness told The ENQUIRER. “But he found an at­tendant to move him into a berth in his car, and they wound up spending almost the entire ride there.”

The roomettes on an AMTRAK are six feet long and three feet wide with two seats that fold down into a single bed. Another upper bed can fold down from above.

“John brought a cooler full of Coronas into the guy’s room,” said the eyewitness. “Then he shut the door, locked it and closed the curtains.

“No one saw either of them until 3 p.m. when they walked to the dining car for dinner. Later that night, when the train pulled into a station in Arizona, John and his pal got off and headed off to some nearby bars for more drinks.

“When the train pulled out, they were back on board and bounced between each other’s rooms, laughing and talking, until the train arrived in Los Angeles at 5 a.m. on March 22. They’d been together for 28 hours straight when you account for the two hours they gained from the time zone change.”

The ENQUIRER has learned exclusively that Travolta’s train buddy owns a photography studio in the Los Angeles area.

The two are said to have been tight for months, and the guy’s studio is filled with pictures of “Wild Hogs” star Travolta.

“He is completely obsessed with John Travolta,” said a close source. “He loves to tell everyone how much John has changed his life and how John is the kindest and greatest guy that ever lived.”

After arriving in L.A. with his pal, Travolta was spotted tooling around Santa Monica in a classic 1970 Mercedes 280SL convertible. Days later, he was in New York City to promote $10,000 Breitling aviator watches.

On March 28 at about 6:40 p.m., Travolta appeared at the Breitling Boutique in Orlando’s Mall at Mil­lenia.

He greeted fans before chatting with a local TV newscaster, who asked about his frequent trips from his Ocala home to Clearwater, which has a Scientology center.

Travolta said that he made the commute every day, and then suddenly mentioned that he’d be flying to California with his children that night to join Kelly. Ironically, The ENQUIRER asked Travolta’s rep for a comment on this story less than an hour after he arrived for the Breitling event!

“John flew out to be with Kelly almost as soon as he knew The ENQUIRER was going to break this story about their separation,” said the source.

“But there’s no denying he and Kelly were apart – and that he was traveling with another man!”