I am black, I am getting old and I am not a smooth talker like the Venetian noblemen. Maybe she IS cheating on me with Michael Cassio.
The signs of Desdemona cheating with Michael Cassio are all there. I heard him talk in his sleep about sleeping with Desdemona and I also saw Cassio wipe his beard with your wife's handkerchief.
Iago told Othello to hide while he talks to Cassio. Iago asks about Bianca (Cassio's prostitute)and whether they are getting married. This question made Cassio laugh and Othello interpret this as if Cassio is gloating about sleeping with Desdemona. In the middle of the conversation, Bianca shows up and throws the handkerchief at Cassio which makes it look like Cassio took it from Desdemona and gave it to his prostitute.
Pray Desdemona, pray and prepare for your death!
But I didn't do anything. I'm innocent!
I killed her, your husband told me she cheated on me.
Othello, what have you done?!
Iago made the whole thing up. I stole the handkerchief and gave it to Iago because he told me to
Othello stabs himself with a weapon and kills himself. Iago is been taken away to be tortured while Michale Cassio becomes governor of Cyprus