In 2004, Britney Spears began a relationship with backup dancer Kevin Federline and after just three months of being together, they got engaged. One small detail though, Federline was still married to actress Shar Jackson, and she was pregnant with her second child with him. They separated before the baby was born, and Kevin went on to marry Britney. On Federline’s relationship with Spears, Jackson said: “wasn’t like just breaking up a relationship. It was like breaking up a family.”
Country singer LeAnn Rimes met actor Eddie Cibrian when they were filming movie Northern Lights in 2009. They fell in love with each other, but they were both actually married. Cibrian was married to Brandi Glanville of Real Housewives of Beverly Hills, who often discusses the affair on the show. Both Rimes and Cibrian divorced their previous spouses in 2011 and eventually married one another just a year later.