After the two enormous events -- Gatsby's admission of love to Daisy and Tom, and the hit-and-run death of Myrtle -- Nick, the narrator, tries to focus on work. He receives a call from Jordan, the woman he has been seeing, and their conversation is stilted and short:
"However -- I want to see you."
"I want to see you, too."
"Suppose I don't go to Southampton, and come into town this afternoon?"
"No -- I don't think this afternoon."
"It's impossible this afternoon. Various--"
We talked like that for a while, and then abruptly we weren't talking any longer. I don't know which of us hung up with a sharp click, but I know I didn't care. I couldn't have talked to her across a tea-table that day if I never talked to her again in this world.
(Fitzgerald, The Great Gatsby, mrbye.com)
Jordan, for Nick, is more than just a love interest; she is a representation of the East Egg world that she and Daisy inhabit. Nick has had his emotions run ragged by events, but Jordan simply wants to return to their carefree life. Her lack of concern for Daisy and Gatsby repulses Nick, and he realizes that their relationship is less than a romance and just barely more than an affair; the most surprising part is that Jordan kept him in such confidence, treating him with more personal respect, but wants to ignore and move past recent events without taking any action or caring who gets hurt. Their relationship compares to Gatsby and Daisy, but is more impulsive and less emotional; Gatsby wants to be with Daisy because he loves her, but Jordan doesn't love Nick, only finds him convenient. It is telling that later she professes astonishment that he broke up with her over the phone; she is used to being the one who breaks up, and unused to being broken up with.