It could have been explained better, but such a dynamic isn't unusual for manga, and unfortunately for real life too.
Jisuh doesn't know the part about Heejae contacting and recruiting his ex boyfriend yet. But he does sense Heejae is manipulative. He just doesn't care because he doesn't want a relationship nor to grow real feelings for Heejae. He just wants the BDSM play to relieve some stress. Heejae however is scheming to make Jisuh fall for him for real.
Ahhh that makes so much sense, thank you! ⁄(⁄ ⁄·⁄ω⁄·⁄ ⁄)⁄
I'M SO ??? CONFUSED???? SO Jisuh knew that Heejae was manipulating him this whole time but hes just.... OK WITH IT ???????? LIKE ????????? WTF