Despite their longstanding romances, these celebrity couples aren't ready to make things official
Liev Schreiber and Naomi Watts
Dating since 2005, Schreiber once presented the British-Australian actress with a ring -- but Watts doesn't think they'll marry any time soon. "It's never been that important to me," she has said. "If it was important to our children, I would do it in a heartbeat."
Credit: Bryan Bedder/Getty Images for Tribeca Film Festival