"They have amicably split but remain good friends who still greatly care for one another," Minnillo's rep tells PEOPLE of the couple, who began dating in 2006.
The split comes after a rash of breakup rumors and reports, which were shot down. Earlier this month Minnillo told PEOPLE that she and Lachey were "very much still on."
A source says Minnillo, 28, and Lachey, 35, are "still friends. It was the right thing for both of them to do."