Kris Jenner is telling it all. The 'Kardashians' star, who was married to Robert Kardashian for 12 years until they divorced in 1991, opened up about why she was unfaithful to the late lawyer.

After Khloe asked her mom why she cheated, Kris opened up about the mindset she had in her early 20s.

"I think being really young and stupid is something that affects you because you don't really understand the consequences of your actions," Kris said.

Kris admitted that all these years later, she still isn't sure if she has a concrete answer as to why she cheated.

“I don't know, because he was such a wonderful husband and such a wonderful father. I think I was in a situation where I thought the grass was greener somewhere else and I made a big mistake. This is the biggest regret of my life."

But despite their split, Kris noted that she and Robert Kardashian remained close until he died in 2003 of esophageal cancer.

However, beyond regrets about the past, Kris admitted that her life is exactly what she thought it would be.

"Everything happens for a reason. I really live my life thinking that God has a plan. And without this whole thing happening, there would never have been Kendall and Kylie," she added.

Kris has with Robert Kardashian daughters Kourtney, Kim and Khloe as well as son Rob; while he has daughters Kendall and Kylie with his ex Caitlyn Jenner.