Chris O'Donnell Reveals the Secret to a Happy Marriage: Don't Go to Bed Angry

Chris O’Donnell is mostly undercover when solving problems on NCIS: Los Angeles as special agent G. Allen. But, in real life, he’s a lot more straightforward.

“I tend to be reactionary,” the actor told PEOPLE about his persona at home with wife Caroline and their five children. “It’s funny there’s stuff that comes up when you first have a baby, you think, ‘how do I change a diaper? What do I do? Is it going to sleep?’ Then all of a sudden the kids become teenagers and you think ‘that was so easy!’ ”

Turns out, running a happy home with five children is something the former Robin credits his wife with. “Caroline is a great mom,” he said while attending the show’s PaleyFest Fall TV Preview at the Paley Center for Media on Friday. “She has great common sense. She is thoughtful, reserved and she takes a breath before she speaks.”

Perhaps those are traits that come in handy after 18 years of marriage. Unfortunately for the rest of the world, part of the secret to what makes the Fentress-O’Donnell household such a great place is only applicable to them.

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“Marry the right person,” says O’Donnell of his marriage advice. “I was very lucky. We work at it all the time and have good communication.

“Somebody told us before we got married, ‘Don’t go to bed angry with each other,’ it’s a little thing but it means a lot. If something is bothering you talk it out.”