Kevin Costner has been unusually open about his private life in recent interviews — mainly in a bid to shore up interest in his teetering vanity project Horizon — according to sources who exclusively tell Life & Style that deep down he’s “in a world of pain,” with friends worrying a full-blown meltdown is just around the corner.

Sources say the 69-year-old A-lister has everything riding on his Western saga, which earned him an 11-minute standing ovation from peers at the Cannes Film Festival premiere in May, but left a lot of critics less than thrilled.

“For all his bravado, he’s terrified Horizon will bleed him dry and he’ll lose a huge chunk of savings,” dishes an insider.

While Kevin is seemingly keeping it together as he makes the rounds to plug his sprawling epic, friends fear he’ll be crying a river if Horizon fails to lure people into theaters, sources say.

“And, of course, all the personal knocks he’s getting are adding to his stress!” confides the insider.

The Yellowstone star was also blindsided when wife Christine Baumgartner filed for divorce in May 2023. The former couple share three children — Cayden, 17, Hayes, 15, and Grace, 14 — and a court battle over child support ensued, with the actor finally ordered to pay the onetime handbag designer $63,209 a month.

But Christine, 50, did not let the tumbleweeds gather before moving on — she’s been dating Kevin’s former bestie, 49-year-old financier Josh Connor, since the split and now there’s even talk that they’re ready to take it to the next level.

By contrast, Kevin’s budding romance with Jewel, 50, has reached a dead end and the “You Were Meant for Me” singer has “given up on him,” a source says. “Kevin never wanted the divorce but that’s the hand he was dealt, but seeing his ex getting ready to marry his old friend, and getting dumped by Jewel — it’s left him bruised!” confides an insider.

“He knows Hollywood and how this works and knows the best way to handle it is to take it on the chin and come back and be less reclusive, which is why he’s putting more of his personal life out there and talking so much.

“But he’s not sleeping well. He’s in crisis meetings over his projects. He can’t seem to get a hit movie, he can’t keep a girlfriend — and his ex seems happier than ever!

“He’s in a world of pain. Everything is caving in on him now. It’s only a matter of time before he crumbles!”