
I feel like the reason Jaeha agreed to let him go there is because Jaeha saw that Yujun dislikes his possessiveness (the "you know how much I hate people touching what's mine"). It was right after that line and the cut to Yujun's unhappy face that Jaeha gave in. I think the possessiveness reminds Yujun of that blonde hyung and he doesn't want a repeat of being fully caged and unable to escape.
Though they're both possessive of Yujun, once again, Jaeha at least tries to treat him like a human. Otherwise, Jaeha wouldn't have initially given him a normal job, kept him out the politics, and looked so worried at the end. Blonde hyung literally uses Yujun to do dirty work and other shit.
Bluetooth connected, your device is ready to pair