A source close to the former couple tells PEOPLE that Sofia, 19, called things off with the 35-year-old reality star after he was with someone else.
“He cheated on her, and she confronted him,” says the source.
Their break-up news on Saturday came after Disick was spotted looking flirty with a mystery woman at Kanye West‘s Ye listening party in Jackson Hole, Wyoming, on Thursday night. Disick reportedly told guests that he and Richie were no longer together, according to TMZ.
However, Lionel condemned the relationship long before Disick’s alleged cheating.
“Lionel hasn’t approved of the relationship since the beginning,” says the insider. “He joked about it publicly but he was livid.”
Still, the source tells PEOPLE that there’s a good chance for a reconciliation between Disick and Sofia.
“It’s likely not totally over,” the insider shares. “They’ve broken up multiple times since they started dating and always ended up back together. No one would be surprised if they’re out again together in a few days or weeks.”
While a source previously told PEOPLE that the music icon wasn’t too pleased about the relationship — “Lionel knows Scott’s playboy ways, and he doesn’t want to see his daughter get hurt,” the insider said — the model had insisted that her dad was on board.
“He’s good — he’s been very nice,” she told E! News at the SAG-AFTRA Foundation Patron of the Artists Awards in Beverly Hills, California, in November.
“He’s very supportive, whatever that means,” she added as Lionel, 68, jokingly pointed a gun-shaped hand gesture at his head.
“I am into her business, and she’s trying to keep me out of her business,” he said.
Another source tells PEOPLE that Disick’s “old issues” contributed to the split.
“When Scott drinks, he is a sloppy mess and fools around,” the second source says.
As for how Disick is dealing with the break up, “Scott seems fine,” the insider tells PEOPLE. “He even thinks she might change her mind. He isn’t really taking it seriously.”
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RELATED VIDEO: Lionel Richie Doesn’t Want to See Daughter Sofia ‘Get Hurt’ by Scott Disick’s ‘Playboy
Sofia and Disick — who shares three kids with ex Kourtney Kardashian — first sparked romance speculation in May after they were pictured cuddling up aboard a yacht in the south of France during the Cannes Film Festival. At the time, Sofia — who previously dated Justin Bieber — adamantly denied anything romantic was going on, tweeting that the two were “just homies.”
Months later, the two had become “inseparable,” a source told PEOPLE in mid-September. They confirmed their romance shortly afterwards with friends in Miami, capping off the trip with a few PDA-packed days in Mexico.