In chapter 2, Myrtle tells the group at her apartment why she married George:
“I married him because I thought he was a gentleman,” she said finally. “I thought he knew something about breeding, but he wasn’t fit to lick my shoe.”
“I knew right away I made a mistake. He borrowed somebody’s best suit to get married in, and never even told me about it, and the man came after it one day when he was out. ‘oh, is that your suit?’ I said. ‘this is the first I ever heard about it.’ But I gave it to him and then I lay down and cried to beat the band all afternoon.”
Myrtle values material things and the money to be able to buy more things. We see her values in this chapter as well when she is with Tom: He buys her things, like a dog and face cream, anything she wants. She thinks her marriage to George is based on a lie because he had to borrow a suit to marry her, but she sees no issue with cheating on him with another man.
For her, Tom has all of the qualities that she thinks George is lacking: money, power, position. Her character even changes when she is with Tom at the apartment in New York City as soon as she changes her dress:
With the influence of the dress her personality had also undergone a change. The intense vitality that had been so remarkable in the garage was converted into impressive hauteur. Her laughter, her gestures, her assertions became more violently affected moment by moment, and as she expanded the room grew smaller around her, until she seemed to be revolving on a noisy, creaking pivot through the smoky air.
However, her actions are, as Nick says, "affected" instead of natural. She does not belong to the same social sphere as Tom and Daisy, no matter the number of possessions or change of dresses that she may have.