Camillo is Vittoria's husband… until he's not… because he gets murdered. We don't really get to learn too much about him, aside from the fact that he's not satisfying his wife sexually, and that his job is to rid the Italian coast of pirates. Poor Camillo's no sex machine, and that gets him killed. Talk about harsh, right? He tries to make excuses, though, telling Vittoria: "Your silkworm used to fast every third day, and the next following spins the better. To-morrow at night, I am for you." (1.2). He's putting off his love-making duties until later. (Of course, there won't be any later, since Flamineo breaks his neck and kills him, making it look like a vaulting accident.)
Yet despite his one… inadequacy… Camillo is connected with important people—particularly his uncle, the Cardinal Monticelso (who becomes Pope Paul IV). Monticelso is one of the main conspirators who try to revenge Camillo's death, getting back at Vittoria, Brachiano, and Flamineo. So, it's nice to know that someone still cares about Cam.