• KATE & SAM photo | Kate Winslet, Sam Mendes

Credit: George Pimentel/WireImage

Published: Monday December 08, 2014 18:00 PM EST

2014

KATE & SAM

Working together on 2008's Revolutionary Road, about a crumbling marriage, may have put a strain on Kate Winslet's real-life relationship with her director husband Sam Mendes, but their March 2010 breakup still stunned friends. "It's really sad; they just grew apart," a source told PEOPLE of the couple's seven-year marriage. "It's tough to be married in this business."