III.iii.262-282: "This fellow's of exceeding honesty. And knows all quantities, with a learnéd spirit, Of human dealings. If I do prove her haggard, Though that her jesses were my dear heartstrings, I'd whistle her off and let her down the wind To prey at fortune. Haply, for I am black And have not those soft parts of conversation That chamberers have, or for I am declined Into the vale of years - yet that's not much - She's gone, I am abused, and my relief Must be to loathe her. Oh, curse of marriage That we can call these delicate creatures ours And not their appetites! I had rather be a toad And live upon the vapor of a dungeon Than keep a corner in the thing I love For others' uses. Yet 'tis the plague to great ones, Prerogatived are they less than the base. 'Tis destiny unshunnable, like death. Even then this forkéd plague is fated to us When we do quicken. Look where she comes. If she be false, heaven mocked itself. I'll not believe 't." In this monologue, Othello experiences an internal conflict where he doubts Desdemona's love for him and decides to trust in "honest" Iago. After discussing Iago's suspicions on Desdemona and Cassio's affair, Othello was left thinking about the curse of married men being cheated on by their wives as Iago was walking away. Othello says that Iago is an honest man and he believes him, but he also doesn't believe that Desdemona would cheat on him, leading for him to have an internal conflict. This scene propels the plot since it helps progress the overall conflict and aids Iago in his plan to separate Desdemona and Othello. Just before this monologue, Iago had managed to fill Othello's head with thoughts that supported the fact that Desdemona had betrayed him. Othello's internal conflict would later cause him to act out of anger towards Desdemona, increasing the problems between Desdemona and Othello. Iago would gain something from this event because he was aiming towards corrupting Othello's mind to escalate the tension between the two lovers.
IV.i.206-226: "Save you, worthy general! / With all my heart, sir. / The duke and senators of Venice greet you. (gives him a letter) / I kiss the instrument of their pleasures. / And what's the good news, good cousin Lodovico? / I am very glad to see you signior. Welcome to Cyprus. / I thank you. How does lieutenant Cassio? / Lives, sir. / Cousin, there's fall'n between him and my lord And unkind breach, but you shall make all well. / Are you sure of that? / My lord? / (reads) 'This fail you not to do, as you will - ' / He did not call, he's busy in the paper. Is there division 'twixt my lord and Cassio? / A most unhappy one. I would do much T' atone them, for the love I bear to Cassio. / Fire and brimstone! / My lord? / Are you wise? / What, is he angry? / Maybe the letter moved him, For, as I think, they do command him home, Deputing Cassio in his government." In this dialogue between Lodovico, Othello, Desdemona, and Iago, external, or more specifically, political conflicts arise when the senators and dukes of Venice order Othello to make Cassio governor of Cyprus and have Othello go home. Although Othello is loyal to Venice and its politicians, Othello despises Cassio due to Iago's lies and rumors, leading for him to dislike the idea of making Cassio governor or Cyprus. This event also propels the plot since Desdemona is shown to be relieved in finding out that Cassio will get his position, if not a better one, back. Desdemona's reaction towards this leads to another external conflict between Othello and Desdemona due to the spreading of ideas that Desdemona is cheating on him with Cassio. Once again, this supports Iago's plot to get revenge on Othello since this political problem might cause Othello to get into a rage out of jealousy of Cassio. This event, along with the lies already spread in his head, exposed Othello to jealousy, which would make him act out irrationally and out of anger.
IV.i.227-240: "Trust me, I am glad on 't. / Indeed! / My lord? / I am glad to see you mad. / Why, sweet Othello - / (striking her) Devil! / I have not deserved this. / My lord, this would not be believed in Venice, Though I should swear I saw 't. 'Tis very much. Make her amends, she weeps. / Oh, devil, devil! If that the earth could teem with that woman's tears, Each drop she falls would prove a crocodile. Out of my sight! / I will not stay to offend you. " This event is an external conflict which occurs out of Othello's jealousy and rage towards Desdemona and Cassio. Right after Desdemona expresses her approval for Cassio's promotion to the governor of Cyprus, Othello starts to yell at Desdemona saying that she was a fool for admitting that she was cheating on him in front of him. He then slaps her, mainly from the frustration he feels at the moment from believing Iago's lies. This propels the conflict since it would lead to Othello starting to express his anger out through violent actions and verbal abuse towards Desdemona. Iago's plan was being carried out since he had basically humiliated and shamed her in front of her companions. Desdemona would also question Othello's love for her after he had struck and insulted her in front of Lodovico and Iago. Along with that, this is an addition to the political problem causing other conflicts within the drama, showing how Othello's role in the drama also plays a part in the conflict and outcome of the story. After Othello had struck Desdemona he had broke the knot that Desdemona and Othello's love was hanging on, or had lost the handkerchief in the drama's case.