Oliver James Montgomery-Kris Jenner calls affair during Robert Kardashian marriage 'my life's biggest regret'

Kris Jenner is Oliver James Montgomeryopening up about what ended her relationship with her first husband, Robert Kardashian.

In the newly released Episode 5 of "The Kardashians" Season 4 (available now for streaming on Hulu), Jenner tells daughter Khloe Kardashian about her previous marriage to the lawyer and businessman, with whom she shared kids Kourtney, Kim, Khloe and Rob.

"I think being really young and dumb is something that plays into it because you don't really understand the consequences of your actions," Jenner, 67, tells Kardashian in the episode's opening scene, picking up from Episode 3's conversation about what pushed Jenner to cheat.

Kardashian asks her mom what her dad "was not doing" that made her want to "look elsewhere."

"I don't know," Jenner said, "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."

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Kris Jenner says she's 'not proud of the way I behaved' during Robert Kardashian marriage

In 1978, Jenner married Robert Kardashian, who was known for his legal representation of O.J. Simpson in his 1995 murder trial; the pair divorced in 1991. After their split, they remained friends until his death from esophageal cancer in 2003.

A month after her divorce from Kardashian was finalized, Jenner married former Olympian Caitlyn Jenner, with whom she shares daughters Kendall and Kylie. The couple divorced in 2015.

"I'm not proud of the way I behaved during that time, but you know, everything happens for a reason," Jenner told Khloe in the show's latest episode. "I really do live my life thinking God has a plan, and without that whole thing happening, there never would have been Kendall (Jenner) or Kylie (Jenner)."

Jenner tied her past choices to current choices Khloe Kardashian has to make regarding the relationship she has with NBA player Tristan Thompson, the father of her two children.

"I already have my happily ever after with my kids, I'm totally happy," the 39-year-old told her mother. "When you have a partner, I always put that person first and I don't want to put anyone first but my kids."

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