Othello describes himself as "one who loved not wisely, but too well." How well do you understand Othello's behavior at the end of the play? Is he still a hero in your eyes? Why or why not?

At the end of the play, Othello smothers Desdemona because he thinks she is unfaithful. Iago has successfully manipulated him into believing that Desdemona and Cassio were having an affair. When Othello realizes Desdemona was innocent, he commits suicide.
While Othello is no longer a hero in my eyes after he kills his wife, I do have sympathy for him. He lived in a society run by an honor code, in which it was expected a man would avenge perceived wrongdoing (such as adultery) with violence; on top of that, Othello was insecure from the start about his ability truly to attract the love of Desdemona. He was a middle-aged black soldier and had to convince others he had won Desdemona's heart honestly, not through magic. He trusted an evil man, Iago, who manipulated him by playing on his weak spot. He lived in a patriarchal culture in which men often relied upon other men more than women, and Iago constantly suggested to him that all women are unfaithful. 
All of the above, however, are explanations and not excuses. Othello acted too rashly; he acted out of his own insecurity and wounded heart, thinking of his own pain more than his wife. Even if it had turned out that Desdemona had been unfaithful, killing her would have been excessive. It is not heroic to murder a defenseless, weaker woman.
Some critics, such as Rene Girard, contend that Shakespeare critiques the honor (or revenge) code throughout his plays, and I agree.