A theme in a literary work is a recurring, unifying subject or idea, a motif that allows us to understand more deeply the character and their world. In Othello, the major themes reflect the values and the motivations of the characters.
In Othello, love is a force that overcomes large obstacles and is tripped up by small ones. It is eternal, yet derailable. It provides Othello with intensity but not direction and gives Desdemona access to his heart but not his mind.
Othello takes Desdemona to Cyprus, the ancient dwelling place of Aphrodite, the Greek goddess of love. But Othello's Cyprus is fortified and dedicated to war, and love has lost its supremacy. Othello believes he is now devoted to love, but by consistently putting war first, he has slighted Aphrodite, and so, although he is victorious in battle, he is defeated in love.
Othello finds that love in marriage needs time to build trust, and his enemy works too quickly for him to take that time. The immediate attraction between the couple works on passion, and Desdemona builds on that passion a steadfast devotion whose speed and strength Othello cannot equal. Yet even his secret enemy, Iago, sees his constant and noble nature and judges that he will "prove to Desdemona a most dear husband." Hating Othello, Iago sets out to prevent that happening.
Iago often falsely professes love in friendship for Roderigo and Cassio and betrays them both. Desdemona's love in friendship for Cassio is real but is misinterpreted by the jealous Othello as adulterous love. The true love in friendship was Emilia's for Desdemona, shown when she stood up to witness for the honor of her dead mistress, against Iago, her lying husband, and was killed for it.
Iago uses the word "love" in a wider and falser manner than the other characters. He tells Roderigo he loves him at moments when he is deceiving him, getting at his money, or persuading him to a course of action from which Iago, not Roderigo, will benefit. Iago tells Othello he loves him at moments when he is whispering the cruelest words into his ear. Iago even says he loves Desdemona, meaning he could feel some sexual desire for her. Iago cannot say "love" honestly: For Iago, love is leverage.
