Nicole Kidman and Keith Urban have a lot on the line as they divorce.

The Oscar-winning actress, 58, and the country star, 57, married in June 2006, and were each established stars in their own right at the time. In the years that followed, they welcomed two daughters — Sunday Rose, 17, and Faith Margaret, 14 — while each continued to garner professional success. Now, nearly two decades later, their shared life is in question as they part ways.

PEOPLE confirmed on Monday, Sept. 29, that the couple had separated after 19 years of marriage. Kidman filed for divorce the following day, Tuesday, Sept. 30.

Reps for Kidman and Urban did not respond to PEOPLE’s request for comment.

Urban reportedly moved out of the Nashville home he and Kidman shared and into a house elsewhere in the Tennessee capital prior to news of their split.

“She didn’t want this,” a source tells PEOPLE of Kidman. “She has been fighting to save the marriage.”

One of the biggest ticket items at stake in Kidman and Urban’s separation: their privacy.

The “worst case scenario” for the couple would be a divorce that results in a messy trial rather than a quiet out-of-court settlement, certified family law specialist David Glass, who is not connected to the case, tells PEOPLE.

(L-R) Keith Urban and Nicole Kidman attend The 2023 Met Gala Celebrating “Karl Lagerfeld: A Line Of Beauty” at The Metropolitan Museum of Art on May 1, 2023 in New York City.Matt Winkelmeyer/MG23/Getty

“Whether it’s two people with ‘W2 jobs,’ a house, a car and a 401k, or it’s celebrities with fancy jobs who are high earners, the worst case is if they go to court and someone is angry and feels like they have to make a point, or there’s a principle that they have to stand behind,” Glass says. “People like that start putting a lot of things into affidavits and declarations, and they feel like they have to air their dirty laundry to show that they were the party who was right and the other party was wrong.”

Details of Kidman and Urban’s relationship dynamics aside, a public divorce trial would likely result in disclosures about their finances.

Nicole Kidman and Keith Urban attend the 55th annual Country Music Association awards at the Bridgestone Arena on November 10, 2021 in Nashville, Tennessee.Jason Kempin/Getty

Most celebrities “don’t want people to know what’s in their estate, where they’re keeping their assets or even the size of their assets,” Glass notes. “The disclosure of that information can all be avoided if the couple comes to a private settlement.”

Should Kidman and Urban divorce, a “confidential divorce settlement” would be “the best possible result,” says Glass.

“In most celebrity divorces that we’ve seen over the last five years, it seems that parties are saying they’re separated, then they get their attorneys and they negotiate an overall deal behind the scenes without anyone knowing what’s going on,” he explains.

If terms are agreed to before filing for divorce, Kidman and Urban can avoid having to file their settlement agreement, per Glass. “That’s the way you keep your private life much more private,” he says. “Once something is filed in the courthouse as part of a divorce, it’s an open record for the public; anyone can look at it.”

The failure to reach an agreement before filing for divorce could mean that the couple’s “entire private lives” could “get exposed in a way that probably isn’t gonna be good for either of their careers,” Glass adds.

Nicole Kidman and Keith Urban attend the Los Angeles Premiere of “The Northman” at TCL Chinese Theatre on April 18, 2022 in Hollywood, California.Axelle/Bauer-Griffin/FilmMagic

The process of reaching an agreement will become more complex if Kidman and Urban don’t have a prenuptial agreement.

“If they don’t have a prenuptial agreement, because Nicole has presumably made more money from her acting career, she would be sharing a larger portion of her money, could be asked to pay child support, and could even have to pay spousal support to him,” Glass says.

Without a premarital agreement, he adds, “every single asset that you’ve accumulated between the day that you got married and the day that you decided that you were not going to live together anymore.”

However, “most people who were already famous in their own right when they got married have business managers and agents, and those people would’ve been talking to them about preparing a prenuptial agreement,” Glass explains.

A prenup “makes the process of dividing the ‘marital’ assets easier” so that “there’s just not that much to argue about,” Glass says.

“The whole purpose of a prenuptial agreement is to protect premarital assets,” adds Marilyn Chinitz, a premarital and family law attorney at Blank Rome in New York City, who is also not connected to the case.

“For example, she has a residence in California. Anything that is titled in her name, anything that is titled in his name, would be deemed separate property in the terms of a prenup,” Chintz tells PEOPLE.

Regardless of a prenuptial agreement that may exist, Kidman and Urban will still have to reach a custody agreement for their two daughters, 17-year-old Sunday Rose and 14-year-old Faith Margaret.

“The one thing you can’t cover in a premarital agreement is anything regarding children,” Glass tells PEOPLE. “So you can’t spell out, ‘If we get divorced, I get the children,’ or ‘If we get divorced, I won’t pay child support.’”

(L-R) Nicole Kidman, Sunday Urban, Keith Urban, Rose Urban, Faith Margaret Kidman-Urban, Antonia Kidman, Craig Marran, guests attend the 49th Annual AFI Life Achievement Award Honoring Nicole Kidman at Dolby Theatre on April 27, 2024 in Hollywood, California.Emma McIntyre/Getty

The age of the couple’s daughters would, however, play a role in determining custody if the case were to go before a judge.

“Any kid who’s 16, 17, or 18, most judges would tell you that kids vote with their feet,” Glass explains. “They can drive, they go wherever they want, and it’s hard to lock them down to a schedule. And they sort of determine, ‘I’m gonna live mainly, for example, with mom, but I’m gonna see dad on weekends,’ or ‘I’m gonna live with them equally.’”

Glass continues, “In most states, kids who are over 14 years old are allowed to express a preference to the court. They can say, ‘This is what I want to do,’ but they have to give a reason why. If the child is considered to be intelligent and emotionally stable and is giving mature reasons for wanting to live with one parent versus the other, the courts generally follow that child’s recommendation, but they’re not locked in.”

Should Kidman and Urban reach a custody agreement privately, “the court is largely going to respect that,” he says.

Keith Urban and Nicole Kidman attend the 2025 Academy of Country Music Awards at Omni Frisco Hotel at The Star on May 8, 2025 in Frisco, Texas.Taylor Hill/WireImage

As the separation has unfolded, “Nicole’s sister [Antonia] has been a rock and the entire Kidman family has come together to support one another,” a source tells PEOPLE.

Another insider says it “really hasn’t been a secret” that the Babygirl actress and the country star have “been living separately for a while now.”

“People close to Keith felt like the split was kind of inevitable,” the source says.

Kidman, who wrapped filming Practical Magic 2 in London in mid-September, shared snapshots of “summer memories” spent with her daughters and extended family in an Aug. 19 Instagram Post.

Urban, meanwhile, has been on tour, with his next stop scheduled for Thursday, Oct. 2, in Hershey, Pennsylvania.

In June, Kidman celebrated her and Urban’s 19th wedding anniversary with a black and white photo on Instagram, captioning the post, “Happy Anniversary Baby ❤️ @KeithUrban.”