"Deryck and I are separating and moving forward on a positive note," wrote Lavigne, 24. "Thank you to all my family, friends and fans for all your support."

Lavigne and Whibley, the frontman for Canadian pop-punk group Sum 41, began dating in 2004 before getting engaged during a trip to Venice, Italy in 2005. They married on July 15, 2006 in Montecito, Calif., when Lavigne was 21 and Whibley was 25. - more on this story