I think every relationship has arguments and expectations that may or may not be unreasonable, it's the ones that can communicate and compromise in a healthy way that tend to last. Hopefully these two gain that. I'm sorry your boyfriend wasn't able to work with you on managing that expectation, that sounds frustrating
It's really cool to see you engaging personally and deeply with the story! I also have some concerns, but from having read the subsequent chapters, I think they'll figure it out, though with a bit of friction periodically. They both need to learn more gratitude/conscientiously respecting what the other is giving, and I think your position is reasonable bc in the long run, chemistry can run out, and the friction can overtake compassion, but I know of a few long term couples that have figured out how to manage huge dispositional differences.
I think more than the rules, the real trouble is that each member in this relationship is a bit myopic about seeing only their own sacrifices and not their partner's.
I mean I know they’ll stay together for the plot but if those characters were irl, they’d be broken up already or it would be a toxic on/off relationship rn. I just hope author doesn’t sweep this under the rug like “tehe he’s quirky!” And doesn’t acknowledge that all of these rules that are one way are an issue of their own but they speak to a greater issue of “oh you just don’t care that I’m uncomfortable” and that knowledge can and does break a relationship faster than anything else. More than love or trust, respect for your partner is the number one relationship make or break factor. I just don’t know is sangwoo has any for his partner rn.
I think they’ll work cause they are def head over heels for each other so eventually they’ll compromise, we all do to keep the ones we love in our lives… the problem with your relationship was that he didn’t seem to do so.. he felt a certain ways and had no qualms telling you to fix yourself without understanding how you feel or why it would be tiring. If he didn’t show signs of understanding after sitting him down to talk then there’s no hope. Without communicating and understanding every human relationship is bound to fail.

He asked me if I could take more interest in his hobbies outside of the ones we share. Valid point right? So of course I said yeah. I did my own research into stuff he likes (history, wars, documentaries and stuff like that) so I could follow along when he talks about them and can ask questions and keep the convo going (which I previously was bad at). Turns out me doing that wasn’t enough. He wanted me to ask questions about EVERYTHING going on in his life. At one point near the end of our relationship, I messaged him and asked how his day was and he got upset that I didn’t ask him about the book he was reading… which I was supposed to remember that two days ago he was reading a book and that he had finished it in those two days. Obviously that turned into an argument but he couldn’t for the life of him understand why I was mad at him because he had already asked me to ask more questions and be more proactive in his hobbies and I had agreed. In my mind, that doesn’t mean I agreed to be a mind reader but in his mind, I should have been asking every single time I talk to him about things that happened a few days ago because I should have known that a book that size would take two days.
Needless to say but I don’t think these two will be good together in the long run. I am biased but this is not an easy mountain to climb and many relationships (including mine) have died on that hill.