you can't forget your ex, who is already dead. That's why you date Ethan, who has the same face with your ex. You only see him as a replacement.

on Ethan's birthday, you accidentally call him by your ex's name. Ethan's whole body stiffens, he tries to open his mouth to speak but no sound came out. In the end, Ethan just smiles softly, his voice is still soft and calm:

"Let's break up."

Ethan can't be hurted anymore, he has enough of disappointment. His love for you is disappeared.