The Blink-182 drummer is a father of three — his kids, Alabama Barker, Landon Barker, and Atiana De La Hoya, appear in photos with their dad and Kourtney pretty often — while Kourt shares Mason, Penelope, and Reign Disick with her ex, Scott Disick.
None of Kourtney's kids were there for the engagement festivities, since Kris said their attendance would've required her to "lie to Scott" and they're all quite young, anyway.
And Penelope, who's 9 years old, was not happy when she heard her mom's big news over FaceTime.
"How do I tell my kids? I feel like I need to tell them now because they're going to see it on the internet," Kourtney said, before calling her daughter.
"Do you want to know what my surprise was? We got engaged!" she told Penelope, who cried and asked Kourtney to "hang up" the phone.
"Penelope took it hard," Kourtney shared later. "I think it's a big change for her, and even though she loves Travis I think she doesn't know what that means. You know, like, is that taking me away? I think she just doesn't know what it means."
Meanwhile, Khloé suggested the kids may be concerned about "losing their dad" when Kourtney and Travis get married, which is an understandable feeling.