Ladies out there…Sam Worthington is now single. The Avatar and Clash of the Titans star and his girlfriend of almost three years, Natalie Mark, have called it quits. A source says the couple was having rough times already. This came quite as a surprise since Worthington rarely talked about his relationship with Mark. We’re sure ladies are happy about this news and it looks like we’ll be seeing more of Worthington in movies now that he’s single.