2013's Biggest Splits
Mamie Gummer and Benjamin Walker
Despite once referring to the Side Effects actress (and Meryl Steep's daughter) as his "Uma to my Keanu," the actors announced they had ended their relationship in March. "It's very amicable," Gummer's rep told Us. The couple, who met while performing on the 2008 Broadway production of Les Liaisons Dangereuses, got engaged in October 2009 and married in July 2011.