Kris and Caitlyn Jenner Only 'Interact When They Have to’ for Kendall and Kylie's Sake: Source

Kris Jenner and Caitlyn Jenner are peacefully co-parenting.

After a few years of tension between the exes, Kris and Caitlyn have put their issues aside for the sake of their children.

“Kris and Caitlyn interact when they have to for the kids,” an insider tells PEOPLE. “It’s important for Kylie and Kendall. They can be cordial, but like most exes, they’re never going to be best friends.”

While Kris and Caitlyn do not spend time together on their own, they’ve reunited on several occasions to support their daughters Kendall and Kylie Jenner.

Earlier this month, both Kris, 62, and Caitlyn, 68, celebrated Kylie’s 21st birthday. The parents stepped out for a family dinner at Craig’s followed by a dance party at Delilah’s in a room decorated with pink tinsel.

Still, a source at the bash says Kourtney, Kim and Khloé Kardashian ignored Caitlyn.

“Things are still frosty between them,” the second source explains. “There are too many hurt feelings between Kris and Caitlyn and the older girls.”

As for how the Jenner parents behaved at the party? “It wasn’t a happy, laughing interaction between Kris and Caitlyn. It was more like, this is a moment where we’re coming together for the kids. It was very brief.”

Just last week, Caitlyn and Kendall were spotted grabbing dinner together in Los Angeles — though Caitlyn previously admitted that she’s struggled to maintain close relationships with her kids.

RELATED VIDEO: Caitlyn Jenner Talks About Her Newest Grandchild for the First Time Since Kylie Jenner Gave Birth

“I spend a lot of time by myself here in the house,” Caitlyn told Broadly‘s Diana Tourjee. “I have a lot of children, but sometimes just because of circumstances, maintaining a close relationship with your kids is very tough. They all have lives. They’ve all moved on.”

The former Olympian, who publicly came out as transgender in 2015, shares son Burt, 39, and daughter Cassandra, 37, with ex-wife Chrystie Crownover; sons Brandon, 36, and Brody, 34, with ex-wife Linda Thompson; and Kendall, 22, and Kylie, 21, with Kris.

RELATED: Caitlyn Jenner Admits Staying ‘Close’ to Her Kids Is ‘Tough’: ‘They’ve All Moved On’

Caitlyn also helped raise Kris’ four children with the late Robert Kardashian: Kourtney, 39, Kim, 37, Khloé, 33, and Rob, 31.

But Caitlyn has become estranged from the Kardashian side of the family, though she maintains relationships with Kendall and Kylie. The Kardashian sisters, as well as Kris, have been open about the fact that passages of Caitlyn’s 2017 memoir created a rift in the family. (In the book, Caitlyn alleged Kris knew more about her gender identity crisis than she says she did.)

“We’re just human beings; we’re going to be here for a very short time,” Caitlyn later added. “We come and we go and at the end, when it’s all said and done, hopefully your family is going to be there.”

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