Court documents obtained by PEOPLE list their date of separation as February 21.
Moniz is asking for joint legal and physical custody of their two minor children — Rio Joseph, 10 and Liam, 15. The two also shared Remy, 23, who is from Grillo’s previous marriage to Kathy Grillo.
The couple, who met on the set of the soap opera Guiding Light in the late 1990s, were married on October 28, 2000.
A rep for Grillo has not commented.
Never miss a story — sign up for PEOPLE’s free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories
According to the LA Times, the pair recently bought a four-bedroom home together in California’s Pacific Palisades in 2017.
Moniz is best known for her work on The Guardian, where she appeared from 2001 to 2004, and on Guiding Light from 1995 to 1999.
She later earned acting credits on Nash Bridges and Damages.
Grillo, best known for his work in the Captain America and Purge franchises, along with the TV series Kingdom and Fight World, will next be seen in Showtime’s Billions and the films Hitman’s Wife’s Bodyguard and Boss Level.