The 56-year-old Space Jam: A New Legacy star couldn't help but joke about the new marriage when speaking to ET's Lauren Zima at the premiere of his new, partially-animated film.
"Our accountant proposed to both of us and he showed us the numbers, and we said yeah, we should probably do it," Cheadle quipped of tying the knot.
He added that the topic of marriage had always come up throughout the couple's lengthy relationship.
"It came up a lot of times. But every time, we were like, 'But we're already together?'" he explained. "He's like, 'Yeah, but this is a better reason to be together.' Really it's because our accountant proposed to us, I wish there were some big sweet romantic story, but the romance happened, you know, the first year."
As for advice for those looking to have a happy marriage, Cheadle joked, "Wait 28 years before you get married. Do not rush into things. Be very careful!"
Coulter gave ET more insight into the special, intimate ceremony adding, "It was just beautiful. It was just for us in our backyard, our two kids. It was for us. It was special."
Just like her husband, Coulter joked, "You've got to make sure. I wasn't sure. Now, I think I'm almost sure."
As for their two kids -- 26-year-old Ayana and 24-year-old Imani -- they didn't seem too excited about their parents finally making things official.
"They were great. They were lovely. They're like, 'OK, Mom and Dad, now you're doing this?'" Coulter said.