"The split happened at the beginning of the year," the insider revealed. "It’s been amicable and they’ve transitioned into a great co-parenting routine. The children are the priority and the heart of the family’s relationship."
The former flames share son Otis Alexander, 6, and daughter Daisy Josephine, 4.
The pair first started dating in November 2011, and the comedian, 45, proposed in 2012.
"I actually came off looking a little cooler than I really am because I had heard through the grapevine, through mutual friends who weren’t exactly her best girlfriends, who would report back, ‘Oh you know, I think she’s dating someone,'" he admitted. "So I didn’t make any moves. I was just very, very busy with other things. And next thing you know, I stopped being busy, she stopped dating someone, and then it was off to the races.
"We sort of reintroduced ourselves," he said. "The universe had more in store for us in the fall."
The blonde beauty told Allure in 2013 that she "kept running" into the Horrible Bosses alum at events. "One night, my best guy friend walked up to him and said, ‘This is Olivia’s number. Use it.’ That was the beginning."
The pair didn’t talk about their plans to get married, but the mom of two, 36, directed her husband in her movie, Booksmart, last year, which she thoroughly enjoyed. "He’s one of the best improvisers in the world so I knew I could cast him," she told PEOPLE. "He’s like spinning a top and just letting it roll. It’s really amazing to see him do his thing."
In honor of Valentine’s Day this year, The O.C. alum took to Instagram to gush about her man.
“We had been dating one month when I went to meet his entire family in Kansas,” she captioned a throwback photo of the duo. “8 years ago. When you know, you know. Also I’ll travel anywhere for good bbq. Happy Valentines, everybody. #justkids.”