Michael Douglas and Tom Cruise's divorce attorney shares the 5 ...

“A lot of couples have a problem that is fixable. But if you have many problems, then the house of cards falls, and that’s when people get divorced,” she tells Fortune.

In the U.S., the average marriage lasts only eight years, and about 40% of first marriages end in divorce.

“You get a divorce because of the totality of lack of communication, loss of interest, distrust, or controllingness. All of a sudden, it becomes insurmountable,” Chinitz says. 

But Chinitz—who has had clients ranging from actors like Michael Douglas and Tom Cruise, to hedge fund managers, private equity founders, and Fortune 500 CEOs—shares the five things she says are key to a loving, lasting marriage.

Chinitz encourages people to look for the best in every situation—even when it’s not easy. “If I look at my own marriage and think about what gave us this long duration—and I hope it continues for many, many years—it’s that I count my blessings. I don’t look at the negatives.”

Even if you don’t look at a marriage like a job, it’s still a lot of work. It takes commitment, communication, and trust to make it successful. Chinitz says she communicates at home just as she would in the courtroom—without raising her voice or letting her emotions takeover, and focusing on the topic at hand.

“I can say something in the most effective way without screaming, I can even inject humor, and the response won’t be to push me away,” Chinitz says.

Chinitz says it’s also important to take time to “celebrate” your love.

“You have to find fun ways to celebrate your marriage. I mean, it could be boring after a while,” she says.

Every week, Chinitz and her husband find something new and fun to do together: eat at a new restaurant, take part in a new experience, go to a museum they’ve never visited.

These outings are just the two of them. “I’m a grandmother, I’m a mother. But the kids and grandkids stay home.”

Independence should be a priority in relationships. Chinitz’s husband goes on skiing trips with his friends, and she goes on biking trips around Europe with hers.

“We allow each other to explore different things, then come back and share those things. When we come back, we bring something else to the table, and there’s a greater dialogue,” she says.

Marriage can be challenging, says Chinitz. And it’s crucial to keep perspective on what’s in and out of your control. If you or your spouse gets sick or loses a job, those likely aren’t factors you can control. But the way you react to one another and how you spend your time is. And that reaction, she says, is key to a lasting, loving marriage.