It's been six years since Kourtney Kardashian and Scott Disick broke up for the final time.
(The couple had called it quits several times before that, but the separation never stuck.)
Kourtney and Scott have maintained a mostly civil co-parenting relationship, and they've both dated other people without incident.
But the peace was shattered when Kourtney started dating Travis Barker.
Perhaps Scott is worried that Kourtney has finally found Mr. Right.
Or maybe he's just had too much time on his hands ever since Amelia Hamiln dumped him,
Whatever the case, Disick is clearly upset about this relationship, and he's having a hard time keeping his feelings under wraps.
From the very beginning, there were rumors that Scott didn't like Travis and felt threatened by the Blink-182 drummer.
The extent of his ill will was made abundantly clear earlier this month, when Disick messaged Younes Bendjima -- who also dated Kourtney -- with the intention of trash-talking their mutual ex.
"Yo, is this chick OK!???? Broooo, like what is this? In the middle of Italy," Disick wrote alongside a photo of Kourtney and Travis making out on a boat while on vacation
Thankfully, Younes wanted nothing to do with such pettiness, and instead of taking part, he publicly called Scott out.
Scott was thoroughly chastised, but unfortunately, it seems the incident did not help him mature.
"Kourtney and Scott are definitely not as close as they once were. Scott has some unsettled ill will towards Kourtney and Travis being together and Kourtney is over the jealousy," a source close to the situation tells Entertainment Tonight.
"She thinks Scott needs to grow up."
Yes, it seems that the best thing Scott can do here is learn to accept the truth of the situation.
Because whether he likes it or not, it seems that the relationship between Kourtney and Travis is getting more serious by the day.
"Kourtney and Travis have grown even closer since traveling together. They have gotten so much more serious, to the point that they could very well spend the rest of their lives together," says ET's source.
"They are both very committed and very happy. Their kids are also excited about a bigger, closer future together."
Kourtney "has helped Travis regain confidence in so many aspects of his life, including flying again, and he can't imagine his life without her at this point."
(Barker was nearly killed in a plane crash in 2008.)
"Travis makes Kourtney laugh and he is honest, sincere, genuinely caring and a great dad, lover and partner," the source continues.
"The list goes on and on. Kourtney loves all of those qualities about him and finds him very endearing."
The insider says that Kourtney and Travis "don’t care about Scott’s opinion, but Kourtney is upset it’s now public."
While it seems that Kourtney would prefer that she and Scott continue their platonic friendship, she has no intention of breaking up with Travis in order to appease him.
"Scott and Kourtney have always had a public united front and have done a great job co-parenting," says the source.
"Kourtney doesn’t want her kids seeing anything online that makes it look like their parents don’t get along."
Yes, Scott's decision to be so public with his pettiness and jealousy is a true betrayal, and it's hugely unfair to Kourtney.
But on the bright side, we're sure he'll soon get distracted by yet another teenage model.