Kanye's Worst Nightmare! Kim Caught In Cheating Scandal With NFL Star

With Kim Kardashian and Kanye West's marriage hanging by a thread, RadarOnline.com has learned that a new cheating scandal could tear them apart once and for all!

A source close to Kardashian, 36, told RadarOnline.com exclusively that her rapper hubby West flipped out over new reports she could be cheating on him with hunky 28-year-old Oakland Raiders NFL star, Marquette King!

Sports blog Terez Owens reported the outrageous claims last week, in a bombshell post that has since been deleted. Kardashian's rep has denied the report. But the insider told RadarOnline.com it still created shockwaves at home.

“Kanye approached Kim about it after reading stuff online and she freaked out on him,” a Kardashian insider told RadarOnline.com. “Kim told him that he should know better than to believe rumors.”

Indeed, this is not the first time that the mother of North, 2, and Saint West, 1, has been accused of being unfaithful.

It is also not the first time that Kardashian has taken a liking to an NFL star! As fans know, NFL player, Reggie Bush, and Kardashian were together from 2007 to 2010. At the time, West was infamously dating Kardashian family nemesis, Amber Rose, 33.

In a 2012 interview with Star Magazine, Rose went on-record to blame Kardashian for her break-up with the Yeezy rapper.

“She's a homewrecker. They were both cheating,” Rose claimed at the time. “They were both cheating on me and Reggie with each other!”

But that’s not all! After Kardashian’s messy divorce in 2012 with her husband of 72-days – NBA star, Kris Humphries – the basketball slammed Kardashian with claims that she had been cheating on him with West while they were married!

During a taping of Khloe Kardashian’s now-axed talk show, Kocktails with Khloe, West accidentally confessed that he and Kim were definitely talking when she was married to Humphries!

“I looked on the Internet, and there was Kim Kardashian with some extremely tall person, and I was like, I need to call her or something,” West confessed while the Kocktails cameras were rolling!

As if that wasn’t bad enough, Kim also slipped about their alleged affair in her book Selfish, writing that she texted West while dating Humphries.

“I just got this Fendi coat and was in New York,” she captioned a photo of herself donning a white fur. “I was in a taxi and took this selfie to actually send to Kanye to see if he liked my new coat. He did!”

“Kanye knows about the rumors that Kim cheated on her exes with him and she knows it too,” the Kardashian insider told RadarOnline.com. “Kim is really upset about all of this right now and she is on a rampage to shoot down the rumor."