The 42-year-old actor and 43-year-old actress confirmed as much in a joint statement Tuesday following months of speculation about the status of their relationship.
"After much thought and careful consideration, we have made the difficult decision to divorce," the couple said. "We go forward with love and friendship for one another and a commitment to co-parenting our children whose privacy we ask to be respected during this difficult time."
Affleck and Garner married in June 2005, and are parents to nine-year-old daughter Violet, six-year-old daughter Sera and three-year-old son Sam. Sources told TMZ the pair will officially file for divorce after they resolve all property and custody issues.
Rumors of a split have been swirling for months, and an insider told FOX411 this week the couple have been living apart for some time. The family was last spotted together on June 14, a month after Affleck was seen without his wedding band on a solo trip.
Affleck and Garner co-starred in Pearl Harbor (2001) and Daredevil (2003), and started dating in 2004. The actor will portray Batman in Batman v. Superman: Dawn of Justice, while Garner is scheduled for Miracles From Heaven with Martin Henderson and Nine Lives with Kevin Spacey.