Scott Disick chose to host a booze-filled event on Friday night at 1OAK in Las Vegas instead of being with his family to support Bruce Jenner.
Now that the parties over, a source close to the Keeping up with the Kardashians clan tells RadarOnline.com exclusively, "Kourtney and Scott had a huge blowout fight over his decision."
"Kourtney was actually really upset about this," the insider reveals. "When Bruce asked Kourtney where Scott was, she had to tell him that he chose to go and host a party in Vegas over being there for him."
"This really hurt Bruce's feelings," says source. "Bruce just said to her, 'Let bygones be bygones.'"
As Radar reported, the 31-year old dad to Mason, 5, Penelope, 2, and 4-month-old Reign was having a hard time telling the couple's children about Jenner transitioning into a woman.
"They are too young to understand," a source said. "As of right now, Bruce is 'Pop-Pop' to Mason and they do not know how they are going to tell Mason Bruce is going to now be a grandma."
According to the source, the struggle to reveal the situation to the kids "has become more challenging."
"Scott has had a very tough time with this and an even harder time explaining it to the kids. He supports this because he has to and not because he wants to."
"But Scott also feels betrayed because there was a point during which he and Bruce got really close. The guys in the family had to stick together. Bruce and ," says the source.
"Now that Rob is gone in his own world and Bruce is no longer wanting to be a man, Scott feels like he really has no one to turn to in that family for some manly advice."
Do you think that Scott was wrong for heading to Las Vegas on the night that Bruce's interview aired? Tell us your thoughts in the comments below.