I think that you will receive many different answers to this particular question. On one hand, I think that both main characters end up having themselves to blame for their downfall. Macbeth's own ambition and Othello's own doubt become the reason for their suffering. Their predicaments are the result of others' lack of care for them, but in the end, I think that both protagonists are able to fully recognize their own role in what happens to them. I think that where a fundamental difference between them might lie is in the role of internal reflection. Othello's demise is shown to be a gradual one, and a state of being where he slowly recognizes that he is "losing it." When Desdemona comes to Othello to wipe his brow in the handkerchief scene, he indicates to her that his headache is so bad that he needs to not receive his guests. This is merely one of many instances where Othello sees himself as falling apart, becoming the victim of internally driven entropy. Macbeth does not display any such reflection, as once his insatiable desire for power becomes increasingly evident, he is merely this kiling machine in the name of power. Where I think an interesting dynamic is met with this is in how both of their characters are shown to grasp what it means to reflect. With his speech about Lady Macbeth, Macbeth shows himself to have understood the implications of both what he did and how he lived his life. It is not an apology, but it is an acceptance of the wrong he did and, perhaps, a chance to sort out the wreckage of his life. Granted, he did not take it. However, the internal reflection evident is present at his end. Yet, Othello does not have one of these moments. There is no grand speech in the drama whereby he understands what he did and how it impacted him. Rather, he simply devolves, killing Desdemona, and little in way of reflection about what he endured is there. It is here where I see instances of similarity between the two is met with divergence.