In chapter eight, Nick visits Gatsby's home in the wake of Myrtle's death and advises him to skip town until things settle down. However, Gatsby refuses to leave until Daisy has made a decision whether or not to stay with her husband. Gatsby is such a hopeless romantic that he refuses to recognize that Daisy is not willing to leave her affluent, stable lifestyle with Tom. From the moment Daisy learned that Gatsby was a bootlegger, she made up her mind to stay with her husband. Nick and Gatsby proceed to have an intimate conversation, and Gatsby reveals the truth about his past.
Gatsby describes meeting Daisy in Louisville for the first time and elaborates on the way he seduced her under false pretenses before heading overseas to fight in WWI. Despite their brief, passionate romance, the distance between them continued to grow while Gatsby was away, and Daisy began entertaining other possible suitors. Nick goes on to offer the reader insight into why Daisy chose to marry Tom Buchanan instead of waiting for Jay Gatsby by writing,
And all the time something within her was crying for a decision. She wanted her life shaped now, immediately—and the decision must be made by some force—of love, of money, of unquestionable practicality—that was close at hand.
According to Gatsby, Daisy felt pressure from her family and society to settle down with someone and desired to have her life shaped immediately. Given the fact that Daisy is a completely superficial, selfish woman, she made the shallow decision to marry an affluent, upper-class man, who would provide her with the financial security and status she desired. Shortly after meeting Tom Buchanan, Daisy married him with some reservations, which she was able to suppress until meeting Gatsby five years later.
In this chapter, Gatsby explains to Nick the history of his relationship with Daisy, describing how the two of them fell in love, to Gatsby’s own surprise, before the war, under the false pretense that Gatsby was a young man from a rich background and able to support Daisy. Daisy even seems to have slept with Gatsby on this basis, although, for Gatsby, this seems to have been, initially, more of a conquest——“he took her because he had no real right to take her hand.”
The intervention of the war and the long wait to be reunited, however, is too much for Daisy, who inhabits an “artificial” world at home far removed from Gatsby’s at the Front. She “wanted her life shaped now, immediately,” something in her “crying out for a decision.” Daisy becomes accustomed again to “moving with the season” and needs some force to tell her what to do; when Tom Buchanan appears, he represents that force.
In Chapter 8, Gatsby explains to Nick (who relays to the reader) the story of how he met and then lost Daisy.
According to Gatsby, he was penniless when he and Daisy fell for one another, but he acted as if he was rich like her and would be able to take care of her:
"...he had deliberately given Daisy a sense of security; he let her believe that he was a person from much the same stratum as herself—that he was fully able to take care of her."
So we assume that Daisy didn't stop waiting for him because of money, since she was led to believe he was rich.
While he was away at war, Gatsby stayed in touch with Daisy, but in her letters she seemed to be getting impatient waiting for him to come back: "—there was a quality of nervous despair in Daisy’s letters. She didn’t see why he couldn’t come." This shows that Daisy loved Gatsby, but she was too impatient to wait an uncertain length of time for him to return and marry her. Gatsby was away at war and nobody knew when the war would end, or who would survive.
Daisy was immature and materialistic, living in a world of money, fashion, and flowers, which throughout the novel symbolize the short-lived beauty of love:
"Through this twilight universe Daisy began to move again with the season; suddenly she was again keeping half a dozen dates a day with half a dozen men and drowsing asleep at dawn with the beads and chiffon of an evening dress tangled among dying orchids on the floor beside her bed."
The beads and chiffon symbolize wealth and parties, and the dying orchid symbolizes Daisy's dying love for Gatsby. Daisy was also impatient and decided not to wait any longer for Gatsby to return:
”She wanted her life shaped now, immediately—and the decision must be made by some force—of love, of money, of unquestionable practicality—that was close at hand."
This means that Daisy made a conscious decision not to wait anymore for Gatsby, because she wanted her life to continue immediately. It might have been love or it might have been money that forced her to make the decision. That was when Tom Buchanan came along, and she married him.