Have Charlize Theron and Sean Penn called off an engagement, which they have never confirmed existed? Us Weekly, citing anonymous sources, said on Wednesday that the couple, together for roughly a year and a half, ended their relationship following a trip to the Cannes Film Festival in May. Theron, 39, ended the relationship, the magazine added. Us had reported in December that the two Oscar winners had become engaged in Paris the previous month, but Theron has never worn an engagement ring. In January 2010, she broke up with her partner of nearly a decade, Irish actor Stuart Townsend. Penn, 54, was married to singer Madonna in the 1980s and to actress Robin Wright, with whom he has two children, from 1996 to 2010.