Conversation so far:
Is Maria Shriver married?
Married to Arnold Schwarzenegger
does Maria Shriver have children?
4
who are Maria Shriver's children?
Katherine, Christina, Christopher, and Patrick Schwarzenegger
what does Maria Shriver's husband do for a living?
She currently does not have a husband
how long have Maria Shriver and Arnold Schwarzenegger been married?
About 25 years
did Maria Shriver and Arnold Schwarzenegger ever divorce?
Yes, in 2011

Question: what caused the filing of the divorce?
Self-contained rewrite: what caused the filing of the Maria Shriver's divorce?