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Myrtle Wilson is married to a man she no longer loves or respects, if she ever felt either of those emotions toward George Wilson. She feels trapped in her marriage and doesn't put a great deal of effort into hiding her disdain for George. Her complete devotion is directed toward her lover, Tom Buchanan, and the fantasy world she shares with him in their affair.
The first time readers of The Great Gatsby meet Myrtle, Tom and Nick stop by the Wilsons' garage/home to tell Myrtle they're going to New York City and she should join them there. The way she treats George when in Tom's presence is indicative of her feelings about the two men.
Walking through her husband as if he were a ghost, (she) shook hands with Tom, looking him flush in the eye. Then she wet her lips, and without turning around spoke to her husband in a soft, coarse voice: 'Get some chairs, why don't you, so somebody can sit down.'
Once Tom and Myrtle are in the New York apartment they use for their entertaining, she can give fuller expression of her opinion of 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...Who said I was crazy about him?...The only crazy I was was when I married him. 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"
Myrtle wanted the financial refinements and social benefits that came with wealth, as personified by Tom Buchanan. She struggled against her legal status as George Wilson's wife until she ran away from George and into the street as Tom's car was driving by.