Kris Jenner Reportedly Cheated on Robert Kardashian With Her Personal Trainer

While many people are well aware of the relationships that Kris Jenner's six children go through, most don't know that the reality star family matriarch might have the most promiscuous past of them all.

In a new book titled Kardashians: An American Drama, penned by New York Times bestselling author Jerry Oppenheimer, scandalous new details about the sexual escapades of the 61-year-old momager have been revealed.

Up Next: Kris Jenner Rocks Yacht Life Amid Rob Kardashian Drama

Jenner, who was known as Kris Houghton before marriage, was involved in several affairs. The men and women who caught her in the act have spoken out in the book.

"The way I knew Kris, she was a good person and then something happened," one of Jenner's closest childhood friends Joan Zimmerman said. "She changed and we weren't seeing much of each other. She was pursuing something else."

Many people that know Jenner say that her mother, Mary Jo Shannon, was responsible for schooling her in the art of seduction.

"I don't want to use a bad term, but I think her mom was pimping her out," she said, according to Daily Mail.

More: Kris Jenner On Kim Kardashian's Sex Tape: 'Haters Are Gonna Hate'

At the age of 17, Kris began dating professional golfer Cesar Sanudo, who was 28 at the time. Sanudo's daughter, Amber Carillo, said that her father was unaware that he was involved with a teenager at the time.

"[Cesar] told me [Kris] told him she was twenty-one, but she was only seventeen, or just about ready to turn eighteen," Carillo says. "He said she fabricated things and didn't really talk about where she came from, about who her real father was, details like that."

Carillo says that Jenner was "being groomed at home" at the time as far as she knew.

"She wanted to be mature and be a golf groupie and try to find a man who had money, that whole thing of just climb the ladder, try to find somebody who was going to get her where she needed to be, wherever that was."

Sanudo popped the question shortly after Jenner turned 19. However, it was around this time that she met Robert Kardashian.

The Armenian lawyer asked her on a date, and Jenner agreed to go to dinner with Kardashian when Sanudo was out of town. The two shared a meal together and later went back to Sanudo's house.

In her 2011 memoir, Jenner claimed that she and Robert were "messing around and heading in the direction of some major hanky panky" when Sanudo arrived home.

Despite her claims, Sanudo's good friend and fellow tour player, Jack Spradlin, says that this was not the case.

"I was out of town and I came home and I caught Kris and Kardashian in bed," Spradlin said.

Jenner married Kardashian in 1978 and the two went on to have four children: Kourtney, Kim, Khloe, and Rob.

Despite living the high life in Beverly Hills, Jenner still couldn't stop her cheating ways.

Jenner then went on to sleep with personal trainer Todd Waterman. She told Kardashian that she was going to the home gym of his best friend, Larry Kraines, for their daily training sessions.

Kraines confronted Jenner and caught her in the act after hearing from his housekeeper that "they were doing something bad," and it was "very quiet down there in the gym."

Jenner allegedly never confessed to the affair, even though Oppenheimer claims that she continued to have a relationship with Waterman.