Iago seems to have no concrete reason to sabotage Othello’s marriage. Yes, he gives hints as to why he is plotting against him but they never seem strong enough, “I hate the Moor; / And it is thought abroad that ‘twixt my sheets / Was done my office. / I know not if’t be true; / Yet I, for mere suspicion in that kind, / Will do as if for surety” (Act I, Scene III). Considering how coldly Iago acts towards Emilia, I doubt the supposed affair between the two emotionally wounded him. I realize he could feel offended that his wife or property (those words can basically be used interchangeably in the play) was with another man. However, if this was the case then Iago could have found a clever way to kill Othello and Emilia. If he really wanted to have an affair with Desdemona then I would not put it past him to rape her and then have her killed. If he is really that upset about not being lieutenant, as he hints, he could have tried having Cassio killed or treating Othello better than he originally was. He obviously wanted Othello to suffer but he never says why.
I think that Iago’s extreme need to create havoc is driven by his bitterness. Perhaps he is envious of Othello’s success and wants to make the general seem like less of a person. It is possible that he has something against Desdemona and wants her killed. In actuality, I do not believe that whatever reason one can come up with to justify Iago’s actions will ever be enough of an answer. Some people have internalized so much bitterness and anger that all they know how to do with those feelings is spread them. Iago knew very well that he had the power to create a big scandal and he took advantage of that. To me, this is enough to explain why he did what he did. I realize that maybe I should not include a quotation from Batman’s butler but his words are too true to discredit, “Some men just want to watch the world burn.”
Image Sources:
https://s-media-cache-ak0.pinimg.com/236x/f6/56/10/f656105c726bd961da188fbc458eefd4.jpg (This kid knows what’s up)
http://www.quickmeme.com/img/d0/d05d28f1edd2add898be50121f4a9b30ab1ac0fb746685bf435e586d5a824d0c.jpg (This is what true bitterness is)
http://www.quickmeme.com/img/89/89f787eb3d2f489133faabdff7abbece36d695662019e22d27691fe3dde058bf.jpg (BURN)