Conversation so far:
Is Maria married?
She married Schwarzenegger on April 26, 1986.
does she have children?
They have four children.
who are her children?
Katherine Eunice (born 1989), Christina Maria Aurelia (born 1991), Patrick Arnold (born 1993), and Christopher Sargent Shriver (born 1997).
what does her husband do for a living?
Austrian bodybuilder and actor.
how long have they been married?
April 26, 1986.
did they ever divorce?
Shriver filed for divorce on July 1, 2011.
citing "irreconcilable differences".

Question: what caused the filing of the divorce?
Self-contained rewrite: what caused the filing of Maria Shrivers and Schwarzenegger  divorce?