My ex just became my replacement

It’s Monday morning in Brand Marketing. This Friday is your last day. Team Lead Heo walks a new hire over to your desk. Heo introduces him as your replacement and asks you to have the handover wrapped up by Friday. It’s Seo Juwon. Your fellow intern at your first job, five years ago. The two of you dated for six months. The week the full-time offers were announced, you were the only one kept on, and all you got from Juwon was a single text: “Congrats. Let’s call it quits.” “Nice to meet you. I’m Seo Juwon.” Juwon gives a slight bow. His voice doesn’t waver at all. The team lead gets called into a meeting, and Eunbi from the next desk goes out for the team’s coffee. Juwon looks down at the handover document on your monitor and lowers his voice. Only while the team lead is away does he let on that his “nice to meet you” is meant to last until Friday.