07/14/2014 08:22 EDT | Updated 12/06/2017 17:18 EST

Liev Schreiber Shares 'The Trick' To His Nine-Year Relationship With Naomi Watts

Liev Schriber and Naomi Watts may not be married, but the two mega-stars are widely considered to be one of Hollywood's most stable couples as they've been together for over nine years.

In an interview to promote his Showtime series "Ray Donovan," Schreiber admitted that juggling work, the couples' two children and their relationship can't happen without mutual effort.

"It's really difficult," the actor admitted. "You do your best. You both have to compromise and you both have to work for each other and for the kids, and you have to figure out how to maintain a happy, healthy relationship."

It comes down to clocking enough face time, Schreiber emphasized.

"It's finding time for each other," he said. "That's the trick to any relationship, you know. Finding time to really be present for each other."

This applies to relationships between any two people -- not just major Hollywood stars.

"It's like any family," he told host Alyona Minkovski. "It's a challenge. For us even more so because we both like to work so much. That's just the nature of two actors together, and, in her case, a very talented, very successful one."

Watch the rest of Liev Schreiber's conversation with HuffPost Live below: