"Abbie ended the relationship with Ryan and she moved out of their home," the actress's representative told People.com exclusively.
Although no reason was given for the split, People.com said it followed months of media reports claiming Phillippe cheated on Cornish.
The couple met in 2006 on the set of the film, "Stop-Loss." Phillippe, who is best known for his roles in "Crash" and "Gosford Park," legally separated from his actress wife Reese Witherspoon shortly after. Phillippe and Witherspoon, who have two children together, were officially divorced in 2007.
Cornish's film credits include "Bright Star," "Elizabeth: The Golden Age," "A Good Year" and "Candy."