What does Nick learn at the party, about Tom and Daisy's marriage?The Great Gatsby by F. Scott Fitzgerald Chapter 2
As Nick accompanies Tom to New York on the train, Tom Buchanan forces Nick to get off with him in the Valley of Ashes in order to "meet my girl." On Main Street they visit Wilson's repair shop where Myrtle Wilson emerges from the office door. After Tom tells her to get on the train, Myrtle does so, but sits in another car. After they step down from the train, Nick, Tom, and Myrtle take a cab to an apartment that Tom keeps for his and Myrtle's rendezvous.
After Myrtle makes some phone calls, her sister Catherine and her husband arrive along with the McKees. As the afternoon progresses, Nick learns that Myrtle met Tom on the train one day, and they then began their liaison. Now that she has seen Tom on several occasions, Myrtle feels entitled to some jealousy of Daisy; however, when she calls out Daisy's name, Tom strikes her with his open hand so hard that he breaks her nose. From witnessing the happenings in the appartment, Nick learns that Myrtle is simply a mistress for Tom's physical pleasure, and he has no respect for her. But, he will not permit her to say the name of his wife.
Evidently, there is something missing in his marriage with Daisy, who herself has seemed distracted and careless in her thinking when Nick meets her in Chapter One. When, for instance, Jordan Baker suggests to her, "We ought to plan something," Daisy replies, "All right...What'll we plan?....What do people plan?" After Tom leaves the room, Daisy abruptly throws her napkin on the table and gets up. When she next speaks it is with "intense gaiety"; however, she admits to Nick that she is cynical, telling Nick that when their daughter was born, she hoped the girl would be "a beautiful fool" since that is the best thing to be. So, from his conversations with both Daisy and Tom, and his afternoon with Tom, Nick perceives that the Buchanans marriage has serious problems and there is much deception in their relationship; things are not what they have appeared to be.