Question

3) Why is tom having an affair? What does myrtle mean to tom? Is tom in love with her?

Answer 1

It is likely that Tom picks Myrtle because he thinks she will be an easy woman to control. She is not wealthy, powerful, or socially connected, so she doesn't pose much of a threat to him. Myrtle also readily accepts Tom's fabricated story about being unable to divorce Daisy because "she's a Catholic."