Kardashian, 40, took a car selfie with Disick and told fans she is “so proud” of their new partnership.
“I’m so proud of the place we’re at as parents to our children now and all the work we’ve put into getting here,” she wrote on Instagram.
The picture came hours after the pair shared a video on their blog Poosh about how they have attempted to move on from their 2015 split while raising their three children Mason, nine, Penelope, six and Reign, four.
Opening up on the “hardest part”, Kardashian told how the pair struggled with introducing their children to their new partners.
She said: “I think the hardest part was when we both started new relationships. That caused fights between you and I, about introducing the kids [to our new partners]. I think that caused the most challenges.”
Disick added: “It’s one of those things you don’t think is ever going to happen, but like everything in the world, you know, things move [on].”
In the 12-minute video, businesswoman Kardashian also revealed that the couple initially had to “go to therapy to talk” because of their communication breakdown.
Kardashian and Disick called time on their nine-year relationship three years ago and have both dated other people.
Disick is currently dating Sofia Richie while Kardashian previously enjoyed a romance with model Younes Bendjima.
Earlier this week Kardashian opened up on her sister Khloe Kardashian's status following her split from basketball player Tristan Thompson, after he cheated on her with family friend Jordyn Woods earlier this year.
She told Ellen DeGeneres that Khloe is in a "really good place," adding that the cheating scandal brought the Kardashian-Jenner family "closer together".