where can you find evidence of Gatsby's devotion to an ideal rather than an actual person?

Gatsby wanted to repeat the past, or at least his illusion of it. Despite Daisy being married Gatsby wants to re-create a time when he fell in love with Daisy. It is an idealized version of the past that Gatsby craves. It's been 5 years since he last seen Daisy. Gatsby wants to ignore the years that he wasn't near Daisy and simply carry on with his fantasy. Gatsby’s fantasy becomes his reality. Gatsby basks in the faint glow of the green light from Daisy's mansion across the bay. He basks in the illusion that Daisy is everything he has built her up as. In reality, none of Gatsby's fantasies are real.