Why did Othello kill himself in Shakespeare’s drama Othello?

Othello, the Moor was a brave soldier, but his mind was rather simple as he could not suspect a person like Iago who knew well how to poison one’s mind gradually by way of presenting himself as a confidant. If Othello captivated the mind of Desdemona, it was because he could tell the stories of his adventures so eloquently that an innocent lady like Desdemona, who was extremely fond of earliest recollections, battles, and sieges, fell in love with him. It was of course Othello’s bravery and nobility that won her heart. On the contrary, Othello’s love for Desdemona was too profound to be conjectured. But the fact is that Othello failed to retain his belief  in Desdemona.  When he was instigated by Iago constantly, he could not think for a while that the relationship between Desdemona and Cassio was rather simple; for Desdemona never loved Cassio as she loved her husband. They had just the wonderful relaxation of spirit which Iago, being cunning and revengeful, exploited. He could do so whenever he realized that Othello’s profound love for his wife might result in unjustifiable jealousy due to the fact that Cassio’s complexion and handsome features might appear superior to the Moor. Othello, being black and a Moor, had his inherent weakness which made him oblivious of his valiant qualities for which Desdemona chose him as her husband amidst many suitors of senatorial rank. Thus, unable to cope with his emotional problem, Othello decided to kill Desdemona. He did so; but he came to know immediately when Cassio was being attacked to be killed, that Desdemona was innocent, and that Iago’s villainy was the cause of murdering Desdemona. He realized that Desdemona was completely innocent. As Othello loved Desdemona very much, he felt great remorse; thus, he had no other way than killing himself to justify his own evil act of murdering his beloved.