Kevin Costner Says His Marriage with Wife Christine Has Been Strengthened During Quarantine

It's the small moments that have meant the most to Kevin Costner as he quarantines with his family during the coronavirus pandemic.

Married since 2004 to Christine, 46 — with whom he has sons Cayden, 13, and Hayes, 11, and daughter, Grace, 10 — Costner, 65, has embraced a new rhythm in his daily life. "I'm really comfortable with my family," he tells PEOPLE in this week's issue. "I'm really comfortable with my children."

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The actor, who returns for the third season of his hit Paramount Network western series Yellowstone, has also learned he has very "normal" kids. "I can feel them working me," he says, laughing. "I can tell when they come to me about something that they've been already told 'no' by their mother."

A dad to four grown children as well (three from his first marriage, and one from a previous relationship), Costner has been honing his breakfast-making skills. "That's the one meal I can handle," he says. As for homeschooling, that's his wife's department.

"I'm computer illiterate," he admits. "I'm so thankful for Christine as a partner. Because they would look at me... and I wouldn't be that guy. And I want to be that guy for the people that love me."

The actor, who is also a musician — his band, Modern West, is releasing a new album, Tales From Yellowstone — says his marriage to Christine has been strengthened during the pandemic. "Our partnership has really come into focus about what we do for each other and how we deal with our family," he says.

It's also a relationship he doesn't take for granted.

"Our house is like a river: You've just got to get into the flow of it," adds Costner, who also stars in the upcoming thriller Let Him Go. "And whatever you thought it was going to be, maybe it still can, but it's going to have to work with what the day brings."