The pair, who have been together for several years, and share two kids, had allegedly been on the rocks for a while but didn't officially part ways until earlier this month.
Following the split, Scott moved out of the Calabasas home they once shared and into the Montrose Hotel in Beverly Hills.
"Scott was here last week. He arrived alone," a source told In Touch Weekly on December 18. However, he didn't stay alone for long. Apparently, he was later joined by a woman -- who was not Kourtney.
"The woman was in her 20s and exotic-looking," recalls patron Thomas Johnson who saw the pair together in the lobby. "She was pulling a small suitcase on wheels and Scott put both his arms around the small of her back, kissed her on the cheek and whispered into her ear. When Scott pulled back, he kept his hand on her hips and leaned back, as if to check her out. The way he touched her and the way they looked at each other suggested they were a lot more than friends. A man with a long-term partner and two children should never behave like that with another woman."
According to a second insider, Scott is planning to move to New York City next month so that he can be "bicoastal." "Kourtney is devastated," said the source. "She always wanted Scott to be the one. Instead, he’s broken her heart."
A third insider tells TooFab that the rumors of a split are untrue and "ridiculous."
Earlier this month, Kourtney's younger sister, Khloe Kardashian officially parted ways with her husband, Lamar Odom, after months of trying to work through his drug use and multiple affairs. Also this year, Kourtney's mom, Kris Jenner, split from her husband and Kourtney's step dad, Bruce Jenner.
Meanwhile, Kim Kardashian and her man Kanye West appear to be going strong.