The couple got engaged at the end of Season 6 of "The Bachelorette" in 2009.
"Ali Fedotowsky and Roberto Martinez have ended their relationship," their representative told UsMagazine.com Monday. "As they go through this difficult time, we ask that you respect the couple's privacy."
The publicist did not offer an explanation for why the pair decided to split up, but an insider told the celebrity news Web site: "Their relationship has been tumultuous since Day 1. They're either extremely happy or they can't stand each other."
"They bring out the worst in each other," a second source told UsMagazine.com.