Final answer:
Daisy Buchanan and Jay Gatsby had a romantic relationship in the past, but they were unable to be together due to societal constraints. Gatsby's actions in the story are motivated by his desire to win Daisy back.
Step-by-step explanation:
The relationship between Daisy Buchanan and Jay Gatsby, which occurred years before the events of the story, was one of romantic connection and unfulfilled love. Daisy and Gatsby had a passionate relationship during their younger years, but due to their different social statuses and external circumstances, they were unable to be together. Gatsby spends years amassing wealth and fame in the hope of impressing Daisy and winning her back.