Kevin Costner denies extramarital affairs in divorce battle with estranged wife Christine

Kevin Costner says he didn't cheat on estranged wife Christine during their 18-year marriage, but he's not sure she can say the same.

Infidelity is now at the forefront of their ongoing divorce battle. According to court documents obtained by Yahoo Entertainment, the Yellowstone actor, 68, says he "does not know for a fact" whether 49-year-old Christine, who filed for divorce in May, engaged in any "extramarital romantic relationships" before their separation.

The documents were filed Aug. 21 — ahead of their child support hearing on Aug. 31 and Sept. 1 as well as a November trial to determine the validity of their prenuptial agreement — and center on Kevin's finances. Christine is seeking all of Kevin’s financial records, both personal and for his 20-plus businesses, accusing him about being "evasive" about his money. The Dances With Wolves director is worth an estimated $400 million.

In an exhibit listing what records she demands he turn over, Christine, a former handbag designer, requests “all statements, receipts, invoices, canceled checks (front and back) and other documents reflecting expenses paid by you, or any person at your request or on your behalf, relating to any extramarital romantic relationships.”

Kevin objected to the demand, calling it “harassment,” but added that he “does not know for a fact if Christine engaged in any ‘extramarital romantic relationships’ before separation and, if so, whether she spent any of his money or charged any expenses in furtherance of her affair(s) on credit cards he paid.” However, he “has no responsive documents for ‘extramarital romantic relationships’ in which he engaged” to turn over “because he engaged in none.”

Rumors have swirled from the start of this bitter divorce that cheating was a factor. In May, there was an unverified rumor claiming he impregnated someone who worked on Yellowstone, which a source close to the actor quickly shot down as “not true.” The next month, real estate investor Daniel Starr, who rented one of the houses on the couple’s beachfront compound in Carpinteria, Calif., denied having an affair with Christine.

Kevin’s first divorce, from college sweetheart Cindy in 1994, involved alleged infidelity on his part, fueling the speculation this time around.

Christine was awarded $129,755 a month in temporary child support — toward the couple’s three children, Cayden, 16, Hayes, 14, and Grace, 13 — until the matter is settled at the upcoming hearing.

The bigger picture is she appears to be gearing up to contest the premarital agreement that she signed in 2004. Christine's lawyers have said she didn’t understand the prenup, giving her a $1.5 million settlement in case of divorce, when she signed it.

According to a new TMZ report, additional court documents filed by Christine state that Kevin’s wealth increased from $100 million to $400 million during their marriage. (He earned $19,517,0641 last year alone, largely fro Yellowstone.) If the prenup is enforced by the judge, his increase of wealth wouldn't matter because their agreement stipulates that all their earnings during their marriage are to remain separate. According to the outlet, she may try to argue that he didn't disclosed his full earnings when the prenup was put in place, therefore making it invalid.

Christine filed for divorce on May 1. Kevin claimed he didn’t want a divorce, and suggested that his wife had secretly planning it for months before pulling the trigger. The divorce quickly became contentious as she wouldn’t move out of the family home, per the prenup, but since has (though to another property owned by the star). He accused her of spending $188,000 a month on plastic surgery bills last year.

In July, Christine was awarded the $129,755 in temporary child support, which was less than half of what she asked for. Those are the broad strokes of this bitter split, with all the different developments along the way — like fights over pots, pans and their Peloton — here.

Last weekend, Kevin and Christine came face to face at a deposition for their divorce. The actor-director is now in Scotland, paparazzi photos show.