AceShowbiz - Are things between %cKendall Jenner% and %cBlake Griffin% already over? Rumor has it that the 22-year-old former Victoria's Secret model and the 28-year-old Los Angeles Clippers power forward are "cooling off" after being together for about three months. But a source assures fans that they are not calling it quits just yet.
"Blake and Kendall have been cooling off recently, but they're not officially broken up," the source tells PEOPLE after Griffin was spotted stepping out with a mystery woman in Los Angeles over the weekend.
The NBA star and the woman in question were seen at Soho Malibu enjoying dinner and drinks with another couple, and according to an onlooker, "They were definitely giving off couple vibes." At one point, the woman allegedly "put her hand in his lap, where he held her hand there for about five to 10 minutes or so."
"It was so subtle," adds the eyewitness. "They seemed very low-key together, and their holding hands looked entirely natural. They looked like they were really comfortable with each other, and they were definitely not calling any attention to themselves and the little bit of PDA that they shared."
Fueling speculation that Jenner and Griffin are on the brink of breaking up, a Radar Online source claims that things between the couple are not working as the "Enchante" babe is "not ready to play stepmom" to his kids, a son and daughter whom he shares with ex %cBrynn Cameron%.
According to the insider, Jenner "is telling friends she's not ready to play stepmom to her baller boyfriend Blake Griffin's kids and is considering dumping him." The model allegedly "was of the impression that he was going to let his ex have full custody of their kids, but now he's talking about joint custody once paternity is established."
While Jenner thinks that Griffin's "a total babe, she's way too young to be herding around another woman's children." However, claimed the insider, her athlete boyfriend "will be furious is she walks."