'KUWTK': Scott Disick Says Sofia Richie Gave Him an Ultimatum Between Her and Kourtney Kardashian

The 20th and final season of 'Keeping Up With the Kardashians' kicked off with some big changes.

As exes and longtime friends, Kourtney Kardashian and Scott Disick have a solid co-parenting relationship, but that doesn't always make things easy in their love lives.

On Thursday's season 20 premiere of Keeping Up With the Kardashians, Scott opened up to Kim and Khloe Kardashian about his relationship with Sofia Richie, which comes to an end when Sofia makes him choose between her and his family life.

"I thought I would give it a try and make her more of a priority, but then even when doing that, she was like, 'I don't wanna share you as a boyfriend with Kourtney,'" he shared. "Instead of just wanting to work with it, she literally said, with an ultimatum: 'You have to choose, me or Kourtney.'"

"And I was like, but Kourtney is Kourtney and my kids. It's a unit," Scott explained. "I said, 'How could you even want that for me?' It just became an impossible relationship to keep carrying on with."

"Sometimes it's time just to cut the cord," Kim agreed. "I get it."

Both Kourtney and Scott have moved on to new relationships since the filming of the season premiere. Scott made things Instagram official with 19-year-old Amelia Hamlin in February, while Kourtney and Travis Barker went public with their relationship in January and have been sharing plenty of PDA in recent months.

However, as Scott said during the KUWTK premiere, no matter what happens in his and Kourtney's love lives, they'll always be there for each other, and for their three kids: Mason, Penelope and Reign.

"I'm never going to give up my relationship with Kourtney and the co-parenting that we have. Nothing in a million years will be worth what we have," he noted. "And I truly believe if the right person were to come along in Kourtney's life or my life, us having children and having this amazing relationship would only be a plus to the outsider."

See more on the upcoming final season of Keeping Up With the Kardashians in the video below.