Arnold Schwarzenegger and Maria Shriver
Fame, Gold Wong/FilmMagic
07/31/2011 at 03:00 PM EDT
Maria Shriver and Arnold Schwarzenegger came together this weekend to celebrate the former governor's 64th birthday, a source confirms to PEOPLE.
Shriver, 55, who filed for divorce
from Schwarzenegger earlier this month, reportedly ate lunch at Beverly Hills restaurant Casa Roma on Saturday before going shopping together.
"Children and family come first," says a source who knows the family.
Adds a second source: "Arnold and Maria will always come together when it comes to supporting and loving their children."
The couple's son Christopher was released from the hospital
Monday after a boogie boarding accident left him with a collapsed lung and broken bones.