Scott Disick threatened to beat up Kourtney Kardashian's new boyfriend.
The 34-year-old reality TV star - who has children Mason, seven, Penelope, five, and Reign, two, with former partner Kourtney, 38 - was furious when she moved on with model Younes Bendjima and he claimed he was going to physically attack him.
In a trailer for next week's episode of 'Keeping Up With The Kardashians', Kourtney read out a text message from Scott about her new boyfriend and said: "He's like 'Your little friend is going to get beat up'."
Kourtney also admitted she was worried about Scott's constant partying and how it would affect their children.
She said: "I'm trying to break the cycle of always being there. I don't want the kids to see him like this.
"We've been in the same pattern, even though we're not together, for 10 years plus and if there was something I could do to help Scott - help his situation or his addiction - I would do it in a heartbeat, but I've learned that it's beyond my control and I've accepted that."
Kourtney previously revealed that when she phoned her ex to tell him she was seeing someone new, out of "respect", Scott - who is currently dating 19-year-old Sofia Richie - began yelling at her over the phone.
Speaking in a confessional on the E! reality show, Kourtney said: "Last night I went to dinner with a guy and was photographed and I just felt like I should give Scott a heads up out of respect, even though he hasn't done the same to me in the past. But the photos never ended up coming out in the end so it was pretty much all for nothing."
And sister Khloe, who had witnessed the phone call, added: "He was screaming at the top of his lungs."