Serena is not like Othello.
One reason why Serena is not like Othello is because of her confidence. Serena is a very self- assured woman. She is George's equal in business and in life. She does not carry herself with any insecurity. Serena assumes a controlling interest in the timber business, expands it to South America, and consolidates her power in a very brash manner. She is determined to exert emotional control on Pemberton to a point where she will eliminate her competition in the form of Jacob and Rachel. Her determination is shown in how she poisons her husband and establishes the way he will die. Serena's focus and drive are significant elements to her character.
Othello's insecurity makes him different from Serena. While Othello exudes confidence on the battlefield, he is different in his personal life. In describing his relationship with Desdemona, Othello says that "she had eyes and chose me." He cannot believe that someone like her would choose someone like him. This reflects an insecurity at the center of Othello's being. It is for this reason that he is susceptible to Iago's manipulations. He is swayed into believing them because he lacks a confidence in both himself and his relationship with Desdemona. When Othello's "occupation is gone," it shows a lack of control. It is difficult to see Serena as one who would lose control. Serena would not allow anyone to take her away from what she desires.
Serena is as study as the lead material that she boasts will form her coffin. She is impervious to external elements, focused on what she covets. She does not possess the uncertain or insecure traits that define Othello and leads to his downfall.