Kourtney Kardashian lashes out at Kim over Rob's secret Engagement

On Sunday's episode of Keeping Up With the Kardashians, a family ski trip turned into a nasty cat fight amongst the Kardashian sisters.

The episode began with Khloé, Kim and Kourtney making a joke by asking each other, "Who's Rob?" – referring to their younger brother Rob Kardashian.

"I think that Rob has his happy life with Chyna," Kourtney told the camera. "But I just hope that it gets to the place where he wants to hang out with his family again.

Later, Kris Jenner decided to bring the entire family to Vail, Colorado for a vacation. In the early stages of planning, she called Rob to ask him to come along, but he was hesitant because it was possible Tyga, 26, would show up and that would be awkward for him. Tyga also refused to come if Rob went, which put Kris in a weird predicament.

In the end, Rob decided to opt out of the big ski trip, which ultimately hurt his family's feelings.

"It makes me so sad, and making another memory without him breaks my heart," Kris told the camera. "This would have been really great for him to connect with the family again."

When Kris later broke the news to the family that Rob and Scott Disick were supposed to go, Kourtney got upset that there could be a chance her ex would drink too much and she would wind up having to "babysit" him. But Disick promised to be on his best behavior, so Kourtney, 37, eventually gave in.

"I just want her to see that I am fine," Disick told the camera.

When they all arrived in Vail, they settled into their family apartment and Kris surprised everyone with having the famous Todd Kraines and his family over for a big reunion. This helped bring a flood of memories back into the house for the Kardashian girls.

Throughout the episode, a whole new side of Kanye West, 39, emerged. He was all about teaching North West, 3, how to ski and how to make snow angels. Yes, West even got down and demonstrated just how to do it for his daughter.

"Kanye has great family morals how he wants us all together," Khloé said to Kourtney. "I love that. It's not at all how I imagined he would be."

As for Disick, 33, he remained on his best behavior, even after Tyga (his party buddy) showed up. He too was big on showing the kids how to enjoy the snowy weather.

Later, at dinner, Khloé, 31, decided to call Rob on Facetime to talk with the kids. As they passed around the phone, they all begged their brother to come, but he still refused.

"It's just a different dynamic when he isn't around," Kim told the camera. "It's just sad. We want memories with him."

Then, Kardashian disaster struck.

When the girls were getting their morning makeup done, they found out that Rob proposed to his girlfriend Blac Chyna the night before at a strip club.

"He proposed in front of her whole family," said Khloé. "That's so f---ed up."

"Rob is such a p---y," she continued to say to her sisters while reading about his proposal on various websites. "I'm not going to cover for him anymore. What am I covering for him anymore for?"

"I don't care if he tells me, I truly could care less." Kim, 35, added, acting as though the news was beneath her. But Kourtney was quick to call her out, and said that she was the one blowing up everyone's phones over the news.

"Maybe he thinks that you guys are judgmental because clearly you are," Kourtney said to them. Khloé and Kim both try to say they don't care, but continue to flip out over the news.

In the final scene, Kourtney continued to defend Rob and called Kim a lunatic because of how she acted, while Khloé admitted to feeling that "someone" was in Rob's ear, forcing him to act this way.

"That's exactly why he didn't tell you, because you're a b----," Kourtney told Kim – which shut her right up.

"Instead of sharing this with his family he keeps pushing us away," Khloé said. "Is someone in his ear giving him this information that he should stay away from us?"

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