"It is a really awkward situation," Disick says, while Kardashian dubs the circumstances "bizarre."
"I want you and Sofia to be comfortable, but it does take a toll on me," Disick, 36, tells Kardashian, with whom he shares three kids -- Mason, 9, Penelope, 7, and Reign, 4. "This trip has so much pressure."
Richie seems to pick up on Disick's change in behavior, telling her boyfriend, "You're a lot more sophisticated with me when Kourtney's around."
"I know we don't have to travel together, and I don't think we'll take every trip together, but it was totally not awkward," she said. "We are doing our best to make everything feel super normal for the kids."
As for Disick, when ET's Lauren Zima caught up with him back in June, he revealed why he Kardashian work so hard to co-parent.
"I think you really got to figure out what's important to you at the end of the day," Disick said. "I mean, there's so many different things that can pull you in different directions. You could look online, and Instagram, and social media, all these things, but at the end of the day -- I mean, you just want to be happy, you want to be content, you want to be comfortable. You want to love the people you are with."
"Life is a challenge and if you work at what you want, you get it. But it takes hard work, as simple as that," Disick added. "You can easily live less of a life without working as hard, and that's up to you."
Watch the video below for more on the former couple.