DiCaprio, 36, and model Refaeli, 25, who have dated mostly on but sometimes off since 2006, "just grew apart and went their separate ways," a source told Page Six on Thursday, describing an amicable breakup late last week.
"Neither were ready to settle down," the source said, "and both have busy careers that have been taking them in different directions."
But wait: "They do this every two years," an Us Weekly source said. "They could be back together next week."
The "Inception" star and Sports Illustrated hottie took six months off in 2009 -- coincidentally the year she was SI's swimsuit-edition cover girl.
-- Christie D'Zurilla
Left photo: Model Bar Refaeli attends the "Alexander McQueen: Savage Beauty" Costume Institute Gala at the Metropolitan Museum of Art in New York on May 2, 2011. Credit: Larry Busacca / Getty Images
Right photo: Leonardo DiCaprio. Credit: Francois Guillot / AFP / Getty Images