How does Daisy's past affect her character as an individual?

Daisy is Nick's cousin, Tom's wife, and the woman that Gatsby loves. She had promised to wait for Jay Gatsby until the end of the war, but after meeting Tom Buchanan and comparing his extreme wealth to Gatsby's poverty, she broke her promise. Daisy uses her frailty as an excuse for her extreme immaturity. Daisy sees her past with Gatsby with a certain amount on nostalgia but not enough to make her leave her life with Tom: a life of old money and the perpetual filthy rich.