Scott Disick and Kourtney Kardashian had to work ''hard'' at their co-parenting relationship.

The former lovers - who split in 2015 following over a decade of dating - haven't always seen eye-to-eye and have both moved on romantically since their break-up four years ago, but have tried to carve out a friendship that will benefit their three children Mason, nine, Penelope, six, and Reign, four.

Speaking to 'Entertainment Tonight', the 36-year-old businessman said: ''I think you really got to figure out what's important to you at the end of the day. 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. You can easily live less of a life without working as hard, and that's up to you.''

The ex-couple get on so well that they even go on vacation together with Scott's 20-year-old girlfriend Sofia Richie, whom he's been dating since 2017.

Kourtney's sister Khloe chimed in: ''And it's hard work for all parties -- I think for you, Kourtney, Sofia, they're all just really strong. I'm really proud of all of them.

''I think they're doing amazing, and I think everyone has to handle their co-parenting situation in their own style, but my mom and my dad were like that.

''It took them years, but my dad would come over once a week for family dinners and would play golf with my stepdad, and so we come from family where we believe in that -- you share children with people, and that's how it should be, and love is love.

''I'm so proud of them, and I'm so proud of them promoting that and hopefully inspiring other people. It's a beautiful thing to get along with each other and for your kids to see that.''