
I'm starting to think "the boundary of delusion" refers to Mokyeon deluding himself that get Nanjo to fall in love with him if he keeps doing those things( the deal and threesome). And to Nanjo deluding himself that he needs to save the twink and to his prejudices towards Mokyeon.
Everything started because of that Twink, but the 3 are in there on their own free will

Ohhh that makes sense , but I have a feeling that Nanjo will fall out of his so called love for twink or maybe he finds out that twink is a big hoe I'm looking forward how it turns out on Nanjo's Pov tbh , he wasn't himself either in last 2 chapter's, more like he enjoyed Mokyeon's company until twink came between them again
Okay so..what we have here is, at first Mokyeon used Nanjo for his own needs, Nanjos soft heart guy who wanted to save the twink got him trapped but then Mokyeon realized he has fallen for Nanjo, brother is confused yet he doesn't know how to keep Nanjo to himself because clearly everything Nanjo is doing is because he likes the twink. But then again the twink got stuck between these 2 ofcourse that guy is nasty but he nearly died this chapter because Mokyeon felt jealous when twink wanted to hold Nanjo hand. so now Mokyeon who feels rejected by Nanjo and got bad reputation ofcourse, he feels defeated yet now this contract shit might be something he might use to get back with Nanjo because that's the only way he can keep meeting Nanjo omg my head hurts also I have a feeling Nanjo is confused about his own feelings with Mokyeon