Iago and Roderigo are arguing. Iago is clearly upset that Othello promoted Cassio over him. Roderigo is also frustrated that he paid Iago a large sum of money to get Desdemona, as well as learn that Othello married Desdemona.
I paid you a large sum of money for you to get Desdemona.
Did you know that the Moor is married to her. As well as promote Cassio, a man with no experience over me.
I am one, sir, that comes to tell you your daughter and the Moor are now making the beast with two backs.
My God, sir, you’re stubborn and suspicious. We come here to help you and you treat us like thugs, but you let an African horse climb all over your daughter. Your grandsons will neigh to you like horses. Your whole family will be ruined.
You are a senator.
What profane wretch art thou?
Thou art a villain
Then Cassio and his officers come to inform Othello to meet with the Duke.
To prison; till fit time Of law and course of direct session Call thee to answer.
By the way Cassio, He's married.
What is the matter, think you?
But after the meeting with Cassio, Roderigo and Brabantio seize Othello.
The duke does greet you, general.
Iago warns Othello of Brabantio wanting to divorce him and Desdemona.
Let him do his spite.
Are you fast married? The duke wants to divorce you.
As the Duke and the senators talk about the invasion of Cyprus, Othello and Brabantio talk to the Duke about Othello's relationship with Desdemona.
Venice. A council chamber.
There is no composition in these news, that gives them credit.
My daughter! O, my daughter!
The duke then says Othello must go to Cyprus to lead its defense. Which Othello can't bring Desdemona along with.
Roderigo is talking about talking his own life, but Iago is there to reason with Roderigo why he should not worry about Desdemona and is calling Roderigo silly.
After all the senators, Duke, Brabantio, Othello, and Desdemona leave.
If thou dost, I shall never love thee after. Why, thou silly gentleman!
I will incontinently drown myself.
After Iago talks to Roderigo, Iago speaks his soliloquy of how he hates the Moor. With his plan to have Cassio with Desdemona.