About 60 friends and family members attended the service, while the couple's 2-year-old twins -- son Lydon and daughter Hartley -- were the ring bearer and flower girl, the website said.
"After 18 years of breakups, makeups, beautiful twins and an unwavering love that provided some pretty damn good song lyrics, we are happy to announce that we are finally married!" the couple said in a statement to People.com.
McGrath is the front man for the rock band Sugar Ray.
Celebrity Couples of 2014 [PHOTOS]