Although ernest hemingway and fitzgerald were friends, why was there a jealous tension between them? had they collaborated, how could they have used their jealousy to create a great work?

They sent letters to each other a couple of times. Many would agree that there is a classic story of the homosexual tensions bubbling just beneath the surface between Hemingway and Fitzgerald, so maybe there you could find room for jealousy. Both of them had strong perceptions of what it meant to be gay, and they stated how to interact with their gay friends. Perhaps if they had worked together, they could have done more for this, let us call it "project".