Affleck is the co-founder of the Eastern Congo Initiative , a grantmaking and advocacy-based nonprofit organization. He is also a stalwart member of the Democratic Party . Affleck and Damon are co-owners of the production company Pearl Street Films . His younger brother is actor Casey Affleck , with whom he has worked on several films, including Good Will Hunting and Gone Baby Gone. Affleck married actress Jennifer Garner in 2005; they have three children together. The couple separated in 2015 and filed for divorce in early 2017.