At this point in Act 1, Othello gives off a calm attitude . He speaks to everyone by their names and is seen as a stable person. As shown above, he is in love with his spouse Desdemona. At this part of the story, he sees her as this sweet and innocent girl who just wants loyalty and love, just as Othello wants from her.
Othello what have you done? You killed a poor soul
At this point in the act, it is seen that Othello goes through major change in mood regarding his thoughts towards his wife Desdemona. From being in love with the woman he goes on to express anger towards Desdemona in this scene. He is also seen reacting in a violent way rather than confronting the situation.
At this point in Act 4, Othello is shown to be influenced under Iago's manipulative tricks. Othello is shown to be quite short-fused in a situation that he doesn't understand yet. Othello's behavior has changed from peaceful to jealous without even beginning to take other things into consideration, Othello falls under Iago's finger.
At this point in Act 5, Othello goes through a wave of emotions by the end of the book. He has the thought that Desdemona is not loving to him and is a cheating “slut” unlike in the beginning of the story. After he goes to end the life of Desdemona with his own hands Othello comes to realization that his actions were uncalled for.