Do you mean the blond guy?
Well it seems that both the blond guy and Candy are originally called Yunjae. So when candy was young they were actually friends but separated after that accident. After that the seme forgot the face of the kid. Some time later he met the blond guy ( well as a kid he wasn’t blond) who was also called Yunjae and had a scar at his wrist. So he thought that he was the kid he met back than. Well they never talked about it so the misunderstanding never resolved.
Thinking that the blond guy was his childhood friend, he became interested in him and over the years I guess kinda fell for him...hope that helped
It's also quite possible that Candy himself doesn't know his own real name. Prologue/Chapter 00 shows a very smol Candy taken in by the Vulture org. So, I think he must have lost his mom after they moved (the day of the accident) and he was raised in the Vulture organization as a spy right from childhood.
He probably only knows bits and pieces of his childhood like the playground etc.
I do think that he knows his real name and some if the past. In one if the latest chapters that women asks him if he is Yunjae and that he felt sorry for his mother, he lies saying that she must habe mistaken him and then thinks that she has been around for a long time. And who knows he might even remember the accident but doesn’t know that it is the seme.
But you could be right too that he has a hard time remembering his past.
Can someone explain about the other love interest of seme? I kinda forgot cuz i just catched up