The pair first met in the middle of the first season of Mad Men. They were introduced through a mutual friend- Vincent Kartheiser, who plays Mad Men's Pete Campbell.
Hendricks got engaged to fellow actor Arend in January 2009 and the couple married on 11th October 2009.
She has said in interviews that her and her husband plan never to have children; instead the couple have a dog Zouzou- a cockapoo.
Happy Wedding Anniversary Christina and Geoffrey!
Source: Wikipedia and The Guardian.