This powerful novel contains ample evidence of Tom's sexism. A great place to start would be his relationship with Myrtle, his mistress, whom he cruelly uses. During the party that Nick attends, Tom clearly shows the way that Myrtle is nothing more than an object to him through how he treats her when she insists on mentioning Daisy's name again and again:
Making a short deft movement, Tom Buchanan broke her nose with his open hand.
This disturbing act of violence demonstrates how Tom Buchanan believes he is more important and "above" women, and how Myrtle exists only to please him. After her death, Tom quickly moves on and shows little grief. As Nick concludes, he is a "careless" person who delights in "smashing up animals and people" for his own selfish amusement. His sexism is clearly demonstrated in his relationship with Myrtle.
The epitome of the chauvinistic male, Tom Buchanan feels that he has impunity regarding his illicit affair with Mrytle Wilson, taking phone calls from her at his very home and having the audacity to invite Nick to join him as he meets Myrtle in New York City; however, when Jordan Baker's behavior is what he considers inappropriate he comments that her family "oughtn't to let her run around the country this way." Moreover, he is outraged when his wife Daisy has the audacity to imitate his behavior. With hostility, he confronts Gatsby, "What kind of a row are you trying to cause in my house, anyhow?" and he declares that he will not allow "Mr. Nobody from Nowhere" to carry on with his wife. When Jay Gatsby declares, "She never loved you. She loves me," Tom dominates Daisy enough to coeerce her, "Just tell him the truth--that you never loved him--and it's all wiped out forever."
She looked at him blindly. "Why,--how could I love him--possibly?"
"You never loved him."
She hesitated. Her eyes fell on Jordan and me with a sort of appeal...But it was done now....
"I never loved him," she said, with perceptible reluctance.
"Not at Kapiolani?" demanded Tom suddenly.
Certainly, in the aftermath of Mrytle's tragic death, Tom further controls Daisy, forcing her to allow Gatsby to become the sacrificial victim of her carelessness in order to guard their social standing. In fact, the scapegoat of her crime watches outside the Buchanan window as Tom leans toward Daisy, probably instructing her what to say and do regarding the accident so that Gatsby will take the blame and become the object of Wilson's hatred. Clearly, then, Daisy's individual expression is subsumed by Tom's domineering personality.