I will die on this hill

not the same. in korean spacing isn’t necessary because it is an agglutinative language.

But if it’s difficult for Sangwoo to read then obviously there’s also a problem with it, no? Having an issue with minor grammar mistakes is a bit much, but spacing? It’s really not a big deal to do that

correct me if i'm wrong, but it's not even all about the spacing in the first place.

sangwoo wanted to change jaeyoung's informal way of conversing—for what? he's texting his lover, not sending an email to his boss or a professor. it's his most comfortable way of texting, he's probably lived his life texting like that with his peers but what, sangwoo wanted him to change such an insignificant trait of his lover just like that? isn't that being considerate?

usually, no one but you should get to say how you want your way of typing texts should be.

Dunno bout that, spacing was the most emphasized thing here. And yeah, sure, you can’t dictate how other people text, but you can make them aware if the way they do it bothers you or makes you uncomfortable. Then both parties have to find a compromise

Actually wagyu is 100% correct. After doing a little bit of research, Koreans don’t normally use spacing outside of formal writing. Because of the way the language is, spacing is not needed. So, yeah, Sangwoo wanted Jaeyoung to write formally to him. Was spacing the most emphasized thing? Absolutely, but only because Sangwoo has a very limited range of what he deems grammatically correct. Is he fully in the wrong? No, this is definitely just a case of miscommunication between the two. Sangwoo probably struggles to understand Jaeyoung’s texts because he’s used to reading/writing formal Korean. I bet Jaeyoung writes the exact same way to his friends and they’re able to understand because they write the same or have seen it online before.

They both need to realize how much the other does for them. As much as Jaeyoung has changed for Sangwoo, Sangwoo has changed for Jaeyoung. At one point you have to draw the line though Jaeyoung’s grammar is not the same as writinglikethis (I would hate it too). They both can’t keep changing for the other because then who you fell in love with is not there anymore. There needs to be compromises on the smaller stuff where you accept the other person is like that and it may get on your nerves but it’s not that big of a deal. Lk feels like their honeymoon phase is coming to a close, meaning they don’t find the annoying stuff endearing. It happens. People overcome it and form healthy relationships.

clocked it.

I said it from the start in another comment that they are both in the wrong. They both don’t see each others sacrifices. Sangwoo was too harsh, and honestly straight up manipulative with the whole “you can’t change this little thing for me so you don’t love me. I don’t mean anything to you”, but Jaeyong is also blind to Sangwoo’s sacrifices (not hobby wise). Sangwoo obv either has autism or is neurodivergent or smth, which means that all these things are incredibly hard for him to change/accept and he already went to great lengths to compromise as much as he can. He’s not being an ass for the sake of it.
As for texting, I would have to ask my Korean friend what he thinks about it.