Yellowstone star Kevin Costner's wife has filed for divorce from the Oscar winner after 18 years of marriage, but their split is not the first turmoil they've experienced. In fact, she gave him an ultimatum before they even married in 2004.

Costner's estranged wife is Christine Baumgartner, but don't go searching for her on social media. Just because the former professional model is private doesn't mean she's meek, however.

Baumgartner was Costner's second wife. He was previously married to Cindy Costner, but they divorced in 1994. He brought four kids into the new relationship, including three with Cindy and one with ex-girlfriend Bridget Rooney, whom he dated before striking a romance with the now 49-year-old Baumgarter. The issue of children is what nearly broke them before they even wed.

The couple met years before they began dating in the late 1990s and went public in roughly 2000, when she was about 25 and he was around 45. In 2003, they broke up — she wanted kids of her own, and he was pretty content.

Spoiler alert: She won that argument, but not by staying patient.

Premiere Of 20th Century Fox's "The Art Of Racing In The Rain" - Red Carpet
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Talking to Parade in 2012, Costner recalled being issued what sounds like an ultimatum.

"She said, 'I'm going to wait for you, but not long. When you come to your senses, come back to me,'" the future John Dutton shares.

"And I did."

Fast forward to 2023, and Costner and Baumgartner have had three kids together: Sons Cayden and Hayes were born in 2007 and 2009, respectively, and daughter Grace was born in 2010. Together they have lived on 160 acres in Colorado (per Brides Magazine).

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Professionally, Baumgartner moved on from modeling to become a successful businesswoman and entrepreneur. Around the time of her marriage to Costner she began Cat Bag Couture, a company that designed luxury purses, handbags and laptop cases. Talking to the Denver Post in 2005, she admitted that Costner helped her get the business off the ground, but the genesis was an idea she had with a friend named Tamara Muro ("CAT" stands for Christine and Tamara). The company's website is no longer active.

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Rumors have swirled around the state of the couple's marriage over the last year and more, with celebrity gossip sites reporting that Baumgartner had given Costner another ultimatum — this time, in regard to his extensive shooting schedule on Yellowstone, which she reportedly asked that he quit to spend more time with his family.

Those rumors appeared confirmed on Tuesday (May 2), when TMZ reported that Baumgartner had filed for divorce from Costner, citing "irreconcilable differences."

A representative for Costner confirmed the split, offering the following quote to TMZ:

"It is with great sadness that circumstances beyond his control have transpired which have resulted in Mr. Costner having to participate in a dissolution of marriage action ... We ask that his, Christine's and their children's privacy be respected as they navigate this difficult time."

Both parties are seeking joint custody, and a prenuptial agreement is reportedly in place.

Costner has been in a very public showdown with the producers of Yellowstone since February; he's been unable to come to an agreement over his shooting scheduling for the second half of Season 5 due to a conflict with another project called Horizon, and according to multiple reports, they've been considering killing off his character and ending the show at the conclusion of Season 5. According to those reports, Paramount Network wants to move on with Matthew McConaughey joining the Yellowstone franchise.

Sources tells Showbiz411 that Costner's character, John Dutton, is expected to die in the first few episodes after the show returns from its current hiatus. The rest of the season will play out the repercussions from his death, and the show might continue for one more season without him.

As part of Taste of Country's comprehensive coverage of all things Yellowstone, check out our Dutton Rules podcast on Apple Podcasts and Spotify.

PICTURES: See Inside Kevin Costner's Spectacular Colorado Ranch

Yellowstone star Kevin Costner lives the ranch life when he's off the set of the hit show, too. The Oscar-winning actor owns a 160-acre ranch in Aspen, Colo., that's a spectacular getaway, complete with a main residence, a lake house and a river house.

The luxury retreat also features a baseball field, a sledding hill, an ice rink, multiple hot tubs and views of the Continental Divide. The ranch property comfortably sleeps 27 people, and it's currently available to rent for 36,000 a night.

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