Kourtney has never been a fan of her ex's relationship with Sofia, who at 21 is 15 years younger than 36-year-old Scott.
“From day one Kourt’s been panicking about this relationship, saying it’ll end in tears and Sofia’s too spaced out and young to be marriage material — let alone a stepmom to her kids!” added the insider.
However Scott isn't having any of it, and has asked her to butt out of his relationship with Sofia.
The source claimed: “[Kourtney]’s taken Scott aside and begged him to think twice before putting a ring on this girl’s finger but he’s told her to back off and stop being bitter.”
Kourtney and Scott, who share three children, Mason, 9, Penelope, 7, and Reign, 4, had a rocky relationship which lasted almost a decade before they split in 2015, got back together, then split again in 2017.
Scott continues to appear on KUWTK and the pair have continued to co-parent since their breakup.