tho that's one of the reasons for their breakup, it's actually because juheon's aunt threatened to ruin dohu's life so juheon used dohu's research for his bl to leave for good, that's why we saw juheon in the countryside working and disguising (black hair), and when his aunt found him, he went back to seoul to become an actor so he could plan to expose his whole family's secret which is the grandfather being hidden from the world by his aunt because she wants the inheritance so much ughhh that old bitch just can't leave juheon and dohu alone,, so yeah that's also why juheon's investigating his aunt so he could have her weakness hahahahaha
I think he's using that as a cover because if Dohu feels like Juheon's pushing him away to protect him he will be like "fuck that" and involve himself further, but if he convinces him that he hates him for using him, Dohu will be more likely to accept it and walk away. I do think it hurt his feelings to find all the research notes but it wasn't completely devastating like he's playing it up, that's why he still showed up at Dohu's house the night before he disappeared just needing to hold him.

Sorry but this whole mess was so avoidable if seme let uke explain everything. Yes it started with curiosity but he was interested in seme in a way. uke never blatantly used him. Atp seme is victimising himself.