Robert Downey Jr. and his wife, Susan, have one rule that has kept their 18-year marriage strong.

During an interview with People, Susan revealed her and the newly minted Oscar winner's secret to a happy marriage is making sure that the family is never apart for more than two weeks at a time.

"We do have a two-week rule, which often feels too long, but we don't go more than two weeks without seeing each other and the family being together," Susan shared, adding, "Fortunately, we prefer to be a traveling circus when we can be."

The producer shares son Exton, 12, and daughter Avri, 9, with Downey. The actor also has a son, Indio, 30, with his first wife, Deborah Falconer.

Susan Downey and Robert Downey Jr.
(From L) Susan Downey and Robert Downey Jr. attend the 96th Annual Academy Awards at the Dolby Theatre in Hollywood, California on March 10, 2024.
(Photo : Frederic J. Brown/AFP via Getty Images)

According to Susan, they make sure to follow the "basic rule of two weeks" regardless of any unexpected developments, such as an illness or a shutdown.

"So you just have to have some basic things in place, and then you have to be willing to flow with the rest of it," she told the magazine.

Downey chimed in, "It just gives me, honestly, something to attach my neurosis to that's positive."

The couple had a busy award season as Downey won several awards, including the Oscar for Best Supporting Actor, for his performance as Lewis Strauss in "Oppenheimer."

The actor paid tribute to his wife in all of his acceptance speeches.

"I'd like to thank my terrible childhood and the Academy, in that order," Downey said at the 2024 Academy Awards ceremony on March 10. "I'd like to thank my veterinarian -- I mean wife, Susan Downey -- over there. She found me a snarling rescue pet, and you loved me back to life. That's why I'm here. Thank you."

Downey and Susan met on the set of the 2003 thriller "Gothika," where she served as producer.

The pair announced their engagement two months later before tying the knot in a Jewish wedding ceremony in 2005.

Last year, the "Iron Man" star marked his and Susan's 18th wedding anniversary with a sweet post on Instagram.

Downey shared a photo from their 2005 wedding ceremony showing him cuddling close to Susan, who held a bouquet of white and pink flowers.

A second photo showed the couple recreating the moment nearly two decades later, this time with her holding sunflowers.

"18 years, love still in bloom!!" Downey captioned the pictures.

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