Numbers don’t dictate beauty, but it’s ‘natural’ for Kourtney Kardashian to compare her and Sofia Richie’s nearly two decade age difference. Here’s why Kourt fights that need to ‘keep up.’

While there’s a 15 year age difference between Sofia Richie, 20, and Scott Disick, 35, the gap widens between the young model and Kourtney Kardashian. At 39, Kourtney is 19 years Sofia’s senior, a fact that can’t always be overlooked — although aging is a beautiful process! “Kourtney is obsessed with looking and feeling young, so it’s natural she’s a little jealous of seeing Scott with a younger woman,” a source EXCLUSIVELY tells HollywoodLife. “She, along with her sisters, do everything and anything to look their youngest.” And when it comes to her baby daddy’s girlfriend, Kourtney “thinks Sofia is young and hot, so of course she feels like she has to keep up.”

But Kourtney doesn’t let jealousy overcome her, and not only because she’s “hot” herself. “At the end of the day though, Kourtney loves Scott dearly and just wants to see him happy and succeed, like any mother of someone she shares children with would,” our source explains. Don’t mistake these small pangs of envy for relationship jealousy, however, since the parents “will never get back together romantically,” our source adds. “If Scott is happy with Sofia, then she’s fine with it.” Being okay with Scott’s new love also makes co-parenting, which is “extremely important” to both Kourt and Scott, less stressful. The former couple, who split in 2015 after dating for nearly a decade, share three children: Mason, 9, Penelope, 6, and Reign, 4.

Kourtney also avoids competition between her and Sofia because she acknowledges how much Scott has grown…since being with Sofia, that is! “He’s grown leaps and bounds since Kourtney was with him,” our source goes on. Anyways, Scott will always be a part of the KarJenner clan, no matter who he’s dating. Our source adds, “Kris Jenner treats Scott just like a son and always will, especially since both of his parents passed away. To Kris, Scott will always be a part of their family and she truly abides by that.” Scott’s rep told HL “no comment” for this story.

The mutual respect goes both ways between Kourtney and Sofia. “Sofia has always thought Kourtney was beautiful, however, she’s not trying to copy or imitate her style or look whatsoever,” a source close to Sofia EXCLUSIVELY told HL, after fans mistook Kourtney for the model in a photo from Nov. 2018.