Kris Jenner Says It Was a 'Huge Mistake' Cheating on Robert Kardashian Sr.: 'My Life's Biggest Regret'

Kris Jenner has pride for a lot of things in her life, but there's one moment that's overshadowed by shame.

During Thursday's episode of The Kardashians, Kris, 67, opened up to daughter Khloé Kardashian about cheating on her father, Robert Kardashian Sr. with soccer player-turned-animator Todd Waterman in 1989, and why she felt it was her "life's biggest regret."

The revelation occurred as the two were chatting about Khloé's ex Tristan Thompson and the Good American founder, 39, asked her mom, "What was your mindset when you cheated?" She added, "When you did that with my dad, and you had four kids and you had a family? Yes, I know you were really young...."

Kris calmly responded, explaining that "being really young and dumb is something that plays into it because you don’t really understand the consequences of your actions."

Khloé still wasn't fully understanding and asked her mom again, "But what was my dad not doing that made you want to look elsewhere?"

Kris then admitted, "I don't know because he was such a great husband and such a great dad, and I think that I fell into a situation where I thought that the grass was greener somewhere else, and I made a huge mistake. That’s my life’s biggest regret."

Kris opened up further in a confessional interview, explaining why she hopes her daughter will think before completing cutting ties with Tristan, who's the father of Khloé's daughter True, 5, and son Tatum, 13 months.

"When I got divorced, Robert and I became best friends. We talked on phone all day long, helped each other through things all the time, and I did have regrets," Kris explained. "I thought, Wow, what I was thinking? So I want Khloé to be really careful when she makes these decisions and she has to let somebody go."

Back in their conversation, Kris told Khloé that while she may have regrets about cheating, she's also pleased with how everything ultimately turned out.

"I'm not proud of way I behaved during that time, but you know what? Everything happens for a reason," she said. "I really do live my life by thinking God has a plan, and without that whole thing happening, there never would’ve been Kendall and Kylie [Jenner]."

Kris was married to Robert Sr. from July 1978 to March 1991. They welcomed four children together: Kourtney, Kim, Khloé and Robert Jr.

Kris met Caitlyn (who publicly came out as transgender in 2015) in 1990, one year before her divorce from Robert Sr. was finalized.

In a recent interview with The Times, Kris revealed that the two "hit it off right at the beginning, and we were married after five and a half months."

"I was infatuated with her, because she was very different from me. But yes, I’d have to say, it was love at first sight," she added.

Kris and Caitlyn tied the knot in April 1991, one month after her divorce from Robert Sr. was finalized. The pair — who share daughters Kendall, 27, and Kylie, 26 — had been together for 22 years when they announced their separation in 2013. (Their divorce was finalized in December 2014.)

Following Kris and Robert's divorce, the exes remained close friends as he skyrocketed to national attention when he acted as an attorney to close friend O.J. Simpson during his infamous 1994 murder trial. He was later diagnosed with esophageal cancer in July 2003 and died less than two months later on Sept. 30, 2003, at age 59.

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New episodes of The Kardashians drop Thursdays at 12 a.m. ET on Hulu.