Sean Penn and Charlize Theron, who first stepped out as a couple early this year, may be headed down the aisle. An insider tells Us that while vacationing in Paris last month, they got engaged, though Theron doesn't need a sparkler, the source says: "There's no ring, but they are committed." Penn, 54, was married to Madonna from 1985 to 1989, and to Robin Wright from 1996 to 2010. Theron, 39, who has a 2-year-old adopted son, has never been married, along with these 10 other celebs. (More Charlize Theron stories.)