The 28-year-old tennis star and 38-year-old singer and actor, who have been dating since 2008, allegedly decided to end their relationship because of their increasingly-busy careers.
A friend of the couple told Us Magazine: "They are two workaholics who couldn't see each other enough. Things happen."
Two weeks ago, Common told Ellen DeGeneres: "Serena and I have been close for about two years. It's been evolving."
He also revealed that he would "love to get married and have kids".