On Monday, another one of Kardashian's exes, Younes Bendjima, called out Disick for alleged DMs Disick sent him criticizing her PDA with Barker during the couple's current vacation in Italy. Our source says that Disick, who shares three kids with Kardashian -- 11-year-old Mason, 9-year-old Penelope and 6-year-old Reign -- is still bothered by her very public romance.
"Scott has always been a little salty and upset about Kourtney and Travis' relationship from the beginning," the source says. "He doesn't love thinking or talking about it. He tries to focus on his own life as much as possible, but sometimes it feels like it's in his face and hard to avoid. Seeing Kourtney and Travis get more and more serious and her move on in this intense way has been a bit of a sore subject.
"Kourtney and Travis are unbothered by everything and in their own little bubble," the source says.
On Monday, Bendjima shared an alleged message from Disick on his Instagram Stories. The message, which contains a picture of Kardashian straddling Barker on a boat, reads, "Yo is this chick OK!???? Broooo, like what is this? In the middle of Italy."
Bendjima replied to the DM, "Doesn't matter to me as long as she's happy. PS: I ain't your bro."
"Couldn't miss this one," Bendjima continued in another slide. "He been playing around for too long, tired [sic] to stay quiet and be the nice guy."
Bendjima also wrote, "Keep the same energy you had about me publicly, privately."
ET has reached out to Kardashian, Bendjima and Disick for comment. Bendjima appears to be referring to Disick and Kardashian's family expressing their dislike for him during the Keeping Up With the Kardashians reunion special that aired in June. When Disick was asked about his ex dating other guys, he jokingly said at the time, "I just want to kill them."
Referencing Bendjima, he added, "Well, the last guy, let's all be honest here." Khloe Kardashian confirmed his assessment, commenting, "Nobody was happy with the last guy."