Robert Downey Jr.\’s Wife Susan Shares the \’2-Week Rule\’ That Keeps Their 18-Year Marriage Strong (Exclusive)

Robert Downey Jr. and his wife Susan never keep the family apart for more than 14 days 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 says in the new issue of PEOPLE, which highlights the actor’s Oscar win for Oppenheimer.

Adds Susan, who shares son Exton, 12, and daughter Avri, 9, with her husband of 18 years, “Fortunately, we prefer to be a traveling circus when we can be.” (Downey is also dad to musician Indio, 30, from a previous marriage.)

But life sometimes brings surprises — as does Downey’s acting career, which can take him to far-flung locations for various projects.

“You keep the basic rule of two weeks, and then you don\’t try and think too far ahead, because so much of what we do is oddly unpredictable,” continues Susan, Downey’s producing partner at their company, Team Downey. “You just never know.”

“Someone might get sick, or there might be a shutdown, or this or that. 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,” says Susan.

Downey relishes the happy home life they have built together. \”It just gives me, honestly, something to attach my neurosis to that\’s positive,\” he quips.

Illinois-native Susan — who met Downey while making the 2003 thriller Gothika, which she produced — points out that her schedule is a little easier than her husband’s.

“The good news is I\’m not in front of the camera, and so as a producer I end up with a little bit more flexibility in terms of location, of where I would need to be,” she says.

“I really admire and have a lot of empathy for couples who both have to be in front of the camera, because you get stuck and you have to make those choices,” adds Susan.

For his first project following his Oppenheimer Oscar win, Downey spends quite a bit of time in front of the camera — as four different characters to be exact — in the HBO series The Sympathizer, which premieres April 14. The espionage series is based on the 2015 bestselling novel from Viet Thanh Nguyen.

Downey, who shaved his head, lost weight and changed the way he walked to portray scheming Lewis Strauss in Oppenheimer, once again pushes himself to disappear in The Sympathzier.

“He approaches everything he\’s done, every Marvel movie, every other movie, with the same level of commitment and belief that he is an actor and that he\’s doing his best to create a role,” says Susan.

“But sometimes I think it looks so effortless that it\’s just like, ‘Oh, yeah, that\’s just Downey being Downey,’ when it\’s like, ‘No, there\’s a lot of craft and skill that is going into the performance,’ ” she says.