Disick, 34 is rumoured to have recently popped the question to Richie, 19 after he was spotted ring shopping and later threw a *celebratory* party.
"Scott says he's dead serious about Sofia, that she's here to stay and is someone he'd like to start a family with," a family insider told Radar Online.
"He doesn't see why everyone's so hung up over the age difference and points out that she's way more mature than any of the Kardashian girls, Kourtney included," the insider adds.
Scott was in an on-again-off again relationship with the eldest Kardashian sis for years, resulting in three kiddies but the pair called it quits earlier this year.
Since then, he has been spotted with a slew of girls waaaay younger than him from Bella Thorne to Madison Beer, but it looks like Sofia is the one, despite the 15-year age gap.
"Scott insists age is just a number and Sofia's his long-term girl now, so everyone had better get used to it."
The source adds that the model has somehow managed to tame Disick.
"To be fair, this is the first of Scott's conquests he's shown any respect to, at least in terms of not cheating on her and being polite when she's on the scene," says the source.
"But the idea he's trying to get her pregnant has shocked even his close friends and they're used to his crazy behaviour!"
The lovers were most recently spotted in Venice, Italy on a cute AF couple vacay.
Could a pregnancy announcement be imminent?
WE CANNOT HANDLE THIS!