Iago uses the word “love” here in a very cynical, free way, making it a combination of lust towards Desdemona and seeking power over Othello, Cassio and Desdemona. At first he sees his seduction of Desdemona as his revenge: “Till I am evened with him, wife for wife”. Then Iago realizes that the jealousy that torments him is the very weapon he can use against Othello, who will be even more susceptible. Iago will lead Othello, via jealousy, to madness: “Make the Moor thank me, love me, and reward me, for making him egregiously an ass”. At the same time, his statements about what motivates him are hazy and confusing. He could be motivated by lust for Desdemona, envy of Cassio, or jealousy over his wife’s supposed affair with Othello; he even suggests that Cassio might also have slept with his wife. It is as though Iago mocks the audience for attempting to determine his motives; he treats the audience as he does Othello and Roderigo, leading his listeners “by th’ nose as asses are [led]”. For each of Iago’s actions within the play, he creates a momentary and unimportant justification possibly to please the audience.
The fifth (and last) appearance of "love" in Iago's soliloquy is most surprising. He will report Cassio's designs toward Othello's wife to Othello so that the Moor will "thank me, love me, and reward me." The word "love" as used in a non-sexual sense is even more powerful. The fact is that Iago loved Desdemona, not just out of "absolute lust". He probably envisioned a sort of three-way love relationship among Desdemona, Othello and Iago. When he didn't receive the promotion, Iago knew that the love he had envisioned was impossible to achieve. Iago's villainy, true and destructive as it is, probably owes a great deal to his feeling that he could not be loved any longer, by both Desdemona and Othello. Iago would then be saying that what is truly at the base of his motivation is that he wasn't "loved" by Othello, that he wasn't included in as part of the team.
This scene is dramatically important for a number of reasons. First of all, it marks the first significant success of Iago, that is, the dismissal of Cassio. It shows that Iago is absorbed with himself and his villainy; he loves that no one sees through his hypocrisy. It reveals more of the plans of his wicked plot and shows the tragic flaw in the character of Othello; Iago will use his jealousy to bring about his downfall. Finally, the scene ends the emphasis on Iago and switches attention to the mind and soul of Othello, which are put into torment by the evil Iago.
In a final passage, spoken by Iago, he takes stock of the present situation and comes to the conclusion that two things are to be done. First he will make Emilia urge Desdemona to help Cassio, and then he will ensure that Othello sees his wife and Cassio together to spark the jealously of Othello, doubting the loyalty of Desdemona. He thinks that she may be sleeping with Cassio because he is young, handsome, charming and white, greatly contrasting with Othello.
