To get top marks in a question like this, when you are writing your paragraphs, you must include three things, which are; citing references from all across the book to show you've read all of it and not just one bit, critical commentary and lastly contextual discussion. To explain my answer I shall pop quotations in directly as necessary, but know that in a real answer you should explain why you are including them, by saying something like, 'and to demonstrate this point, Othello's statement that ...'
Firstly, we may talk about how his ending is indeed self inflicted. Othello himself admits that he is a jealous creature, and he was letting the emotion get the better of him. 'The green-eye'd monster that doth mock me'. Furthermore, throughout the play, Othello's constant need for proof alludes to the fact that he is much more jealous than he is letting on: 'I'll see before I doubt;when I doubt, prove; I and on that proof, there is no more but this'. Indeed, in the end, Othello is the one who proclaims his own guilt; 'Twas I that killed her'. T.S. Eliot called this mounting of jealousy a 'terrible exposure of human weakness'. Thus, his own jealously that he lets grab a hold of himself, results in his demise. Another idea may be that Othello's disappointment with love results in his demise. On paper the two were well suited, both glamorous; he a highly regarded man of War and she a beauty beyond compare. However, as is obvious when we read the prose, the marriage is ill fated, with the two not really understanding the other's intentions or personalities. Indeed, Kenneth Muir writes that Desdemona fell in love 'with his autobiography rather than him'.
Another take on the question may be that rather than his demise being self inflicted, it was actually a direct result of Iago's manipulation. The cast, at the beginning of the piece are absolute in their trust of Iago- which we can see through the monosyllabic, decisive use of language used in reference to him; ''Honest Iago...O brave Iago'. However, his manipulative ways soon came to the surface. A good example of commentary to put here would be EAJ Honningmann's statement- ''Pretending honesty and good will, he persuades others to accept his version of events'. This manipulation is fundamentally evil and drives Othello into such a rage that he acts out the murder as a result. Indeed, Coleridge said once that Iago was 'a being next to the devil'. This idea of Iago being evil can be found in Shakespeare's prose- 'Hell and night/ must bring this monstrous birth to the world's light'. We must now bring in some ideas about context- one idea may be to bring in some facts about witchcraft at the time- which was a prevalent fear!
The last aspect of the answer to the question revolves around the idea that Othello and Desdemina had an ill fated relationship from the start and was doomed to fail, no matter what either of them did. At the time, society was still very racist, and so a relationship between two different races would have been viewed as suspicious. Throughout the play, Othello's African descent is exaggerated- 'Lascivious Moor'. While on the other hand, Desdemona's fragility and tenderness and also exaggerated- 'So tender, fair and happy'. Indeed, Dr Johnson, a critic of the time, claimed that the play was ' a useful moral not to make an unequal match'. Again, you must now talk about context, and racism at the time.
So, in answer to the question we have discussed that perhaps Othello's demise was not as a result of his own failings but rather a multitude of problems. But remember, the only way to get those top marks is to include bits of commentary and context! It's all very easy to find; historical facts online or jStor, I have a large library of useful contextual stuff and critical commentary which you are more than welcome to use!