When Sofia Richie went out to dinner at Nobu Malibu with Scott Disick and his children on Jan. 26, it was the first time she was seen with Mason, 8, Penelope, 5, and Reign, 3. Turns out, it was a date night six months in the making.

Back in 2015, when Kourtney Kardashian and Scott split up, she set a rule. “She told him he had to be in a relationship with someone for at least six months before letting her near the kids,” says an insider. Scott, 34, finally reached that milestone with Sofia, 19, “so Kourtney gave Sofia her blessing to meet the kids.” First, though, Kourt, 38, “insisted on a one-on-one meeting,” the insider says. “She needed to ensure Sofia is responsible enough to play stepmom — and Sofia passed the test!”

scott disick sofia richie getty images

Yet despite Kourt’s approval, she’s not exactly happy they’re dating. “He’s convinced Kourtney is jealous that she’s been replaced by a hot, younger model, who also comes from a famous family,” a separate source exclusively told Life & Style. “Kourtney also secretly feels betrayed by Sofia, as she’s known the Kardashians for years and yet still pursued Scott. Kourt feels like Sofia has stabbed her in the back.”

The couple’s large age gap is not only a cause for concern for Kourtney, but is also costing Scott serious earning-potential. He gets paid tens of thousands of dollars to make appearances at 21-and-over clubs, but lately, he’s been canceling gigs if underage Sofia can’t join him.

“He used to come to Las Vegas at least once a month and make six figures,” the source continued, “but he stopped because Sofia can’t be in the clubs with him.” He’s losing money, “but that’s not his priority right now. His priority is dating her.” The first source added that until Sofia, “none of Scott’s girlfriends were allowed to meet the kids.”

Scott and Sofia are shacking up! Watch the video below for details on their new digs.