Khloé Kardashian, 31, reportedly confronted new boyfriend James Harden, 25, about cheating with another woman, Australian model Rochelle Relf.
According to RadarOnline, the "Keeping Up with the Kardashians" star "truly believed she had found a good guy in James, even though their age difference concerned her."
"The chemistry was really strong and intense, and Khloé thought this was someone she could get serious with," a source revealed.
However, Kardashian supposedly had to confront Harden after Relf recently exposed to the public that she slept with him.
What was the NBA star's response? "James denied hooking up with the woman, but Khloé just doesn't believe him."
The latest report follows Relf admitting to Australian magazine New Idea that she spent the night with Harden in June at The Star, a casino in Sydney.
"Khloé was with James in Hawaii, then he flew to Australia and spent the night with me," she said. "He was charming, affectionate -- he asked me to visit him in America and told me he was a single guy."
The blonde beauty also mentioned that the athlete, who was dating the reality star at the time, was pressing her for questions on whether or not she was single.
"I don't want to hurt Khloé," she insisted. "But as a woman I think we need to hear these things and she should know the truth. James is very good at making himself out to be a loyal person."
'He is Mr. Romantic and says what you want to hear," she added. "But he is in no way ready to be settling down and it's no secret Khloé wants a family."
Meanwhile, Kardashian and ex-husband Lamar Odom are reportedly expecting a baby following their recent divorce.
The "KUWTK" star was supposedly seeing both basketball players at the same time.
"The fact is, she would consider being exclusive with James if it weren't for Lamar," an insider told OK! Magazine.
The insider also revealed that Kardashian partied and slept with Odom in Las Vegas earlier this month, and is sure that her ex is the father of her child, since she did not hook up with the Houston Rockets shooting guard on that weekend.