Lily was the daughter of Hector Rivera, a Puerto Rican crime boss who was a rival of Sonny's. Lily and Sonny had a relation ship during the whole Sonny/Brenda thing. They eventually married, but Sonny was just about to leave Lily for Brenda when he found out she was pregnant. Sonny told a devasted Brenda he couldn't ever leave Lily now. FYI - He really did love Lily, he just wasn't in love. Anyway, Hector had discovered Sonny was going to leave Lily (but Hector didn't know about the baby) so he rigged a car bomb to go off. Unfortunately, in the famous "Clink/Boom" episode, just as Jax and Brenda toasted their wedding on a yacht, a pregnant Lily started the car and was blown to bits by the bomb her father had rigged to kill Sonny.