Kevin Costner 'Doesn’t Know Who to Trust' After Estranged Wife Christine Jets Off on Vacation With Actor's Close Friend: 'He’s Sick Over It'

Kevin Costner and Christine Baumgartner's divorce keeps getting worse.

After Baumgartner, 49, went on vacation with one of Costner's close friends Josh Connor at the Four Seasons Resort in Hawaii, the actor is apparently fuming about the situation.

“Kevin doesn’t know what to think or who to trust,” a source dished. “He’s sick over it.”

"If Christine’s doing this to upset Kevin, it’s working,” the insider said. “Josh is someone Kevin trusted — they’ve been playing golf together for years."

The model's island getaway with Connor “is a huge slap in the face” for the Yellowstone star, said the source. “Kevin’s stunned that Josh, who he’s known for years and considers a very good friend, would go on vacation with Christine. He’s being told there’s nothing going on, that they’re strictly friends, but he finds that hard to believe. And even if that’s true and Josh is just offering Christine a shoulder to lean on, Kevin still feels incredibly betrayed," the insider said.

Over the past few weeks, the 68-year-old star has been battling it out with his ex — from child support and living arrangements. The former flames, who split in May, share Cayden, 16, Hayes, 14, and 13-year-old Grace.

As OK! previously reported, Baumgartner officially moved out of their home after a judge ruled she must leave by July 31, according to the couple's divorce proceedings.

"Christine is following the legal advice per the prenup and is vacating the family house," the insider stated of the Friday, July 28, move, adding that Baumgartner "will stay at a smaller house on the property that’s been used as a staff quarter."

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"This is a temporary solution," the source explained of the relocation. "She is still looking for another house. She is staying in the area to not disrupt the kids' lives. They will be back at school in the fall with their friends. Christine is trying to keep everything as normal as possible. Her sole focus is the kids."