Since I read this digitally and couldn't find any information on the chapter breakdowns for the volumes, I'll just write my overall thoughts here.
There's a fair amount I liked, and I can definitely see why this would be a favorite for people, especially if it was one of their earlier experiences with the genre. I enjoyed the character progression with Ahn Jiwon, particularly the whole symbolism with the mask (both literal and figurative) - that final scene was almost good enough to make me reconsider my overall rating.
I liked Nam Dong-Gyun's backstory, too, once we finally got it, and the whole concept of how life might have been kinder if these two sensitive, queer boys had met in high school - having the chance to spend time with kindred spirits rather than being hurt and thrown aside by people who didn't understand them.
With that said, I'm honestly not sure I ever really felt their chemistry. There's also a lot of sex, which would probably be a plus for most readers, but it felt imbalanced to me, especially because a lot of the scenes were just angry f*ck buddies, essentially, until Jiwon finally started to fall for Dong-Gyun and tried to slowly soften their encounters into actual affection. Still, they seemed so much more focused on the physical and hardly spent time talking, which...yes, I'm more interested in. I want to see them getting to know and like each other as people.
And honestly, it's not all negatives on Jiwon's side; Dong-Gyun being an obsessed fan who got to sleep with his favorite online streamer was a little uncomfortable, too.
I'm glad that he ended up apologizing for ruining one of Jiwon's streams - because while Jiwon was being a total jerk to him for the initial stages of their relationship, Dong-Gyun was also breaking a lot of the rules they'd set out, and pushing past the established boundaries. It just wasn't particularly healthy for either of them, until much later in the storyline, when they finally started to communicate more as equals.
I will say the one scene I didn't like at all was the random bit of watersports - which is a Hard No for me, enough that I might have skipped this entire series if I'd known it was included. It was fairly brief and not super graphic, though, and also 3/4 of the way through the story, so I just kept going. (But it was something that swayed me into not needing to own the physical volumes.)
What's kind of funny is that this was between the main couple, not the dom/sub side couple - you'd think it would've fit better with their dynamic, as a sort of humiliation kink. But honestly it kind of felt like Mingwa was trying to pack in spicier and more dramatic sex scenes without necessarily feeding them into the story or character progression.
I did like Dong-Gyun's friend a lot, though, and I enjoyed the final side story of him and MD developing an actual romantic relationship outside of their dom/sub play sessions. It's an interesting dynamic - BDSM isn't something I'm particularly into, but I think this was a fairly good portrait of two adults pursuing something they're mutually interested in. I found the separation between play and romance interesting, too, because I've actually known some people who do that in real life, and I think it's good to portray different kinds of stories to speak to different people. Not everyone loves in the same way, and that's okay.
Again, there was one bit that ruined it a little for me, though, and that was the scene with MD forcing Chanwoo into a sex scene with the guy who'd just broken Chanwoo's heart. Like....an hour earlier. I know it was a BDSM scene, and that they all had safe words and Chanwoo was choosing not to use his, but it still felt incredibly cruel on MD's part...and not in the sexy dom way. He was damaging Chanwoo emotionally, which leaves a deeper kind of bruise.
They did ultimately talk about it...kind of. I saw people in the comments saying that MD was trying to push Chanwoo to use his safe words properly, which is a good take, although not really how I read the scenes, based on how MD spoke to him after. But they did have a breakthrough in some ways, and hopefully that leads to more honesty and true vulnerability for them both in the future.
An interesting series, definitely; I see its value, but I really don't think it's one I'd go back to revisit.