Who's To Blame?

So many deaths and no one to take the blame for them. People tend to pass on the responsibilities for their actions all the time. In Othello, the initial cause and responsibility of Desdemona's death seems to be passed around. It is her husband who kills her; but only because of her supposed cheating on him, he seems to believe he has the right to murder her. We could go past those two and blame Iago for her death, since he is the one who tricked Othello into believing the legitimacy of her affair with Cassio. However, Iago is taking his revenge on Othello since Cassio received the military position that he was hoping to receive from Othello. It ends up being a stupid case with no one having a legitimate case on their hands, so in the end, who's to blame?