My (quite long) opinion about this

I know a lot of people are complaining about how the story turned out, but I think it was predictable pretty much from the start that this wouldn't be a fluffy type of manhwa. Don't get me wrong, I understand that this isn't for everyone, but I also would like to say that it's a very good representation of how toxic a relationship can be, and how love sometimes isn't enough to make it work. It brings up heavy subjects, like domestic violence, pedophilia, depression, alcoholism (I guess?) and such, so I definitely wouldn't recommend it to anyone, but still.

Now, I would like to dive in more in their dynamic, because as I said, it's a very great representation of how toxic a relationship can be, which hits close to home, since I used to be in yujun's place with a previous partner. Since I've seen a lot of hate toward Jiho in the comments, I would like to explain that this kind of personality is very easy to hate on and blame for the relationship to fail, because, yes, those kind of people definitely challenge most people's vision of what a victim of abuse it ought to be. Even in medias, victims are often depicted as kind, innocent, gullible, and we barely ever hear of victim's flaws, or when we do, the public's opinion completely switch up on them (like Amber Heard for example (I'm not here to argue about whether or not you think about her as a victim, the thing is that I do, and that's all I'll say about that)). Also, I know we often hear that having traumas isn't enough of an excuse to treat people badly, that we should be the ones ending the cycle, things like that ; that is true in a way, because no one deserves to suffer because someone around them hasn't healed from whatever they had to go through before.
With that said, I would like to say that sometimes people aren't in capacity to break the cycle, sometimes because they're not in a good enough mental state, sometimes because they don't know how, and sometimes, they just aren't aware enough of the way they mistreat others. What I'm saying is, I understand how hard it is to forgive people like Jiho, because I used to hate the partner I had who was very similar to him, and always blamed them at the bottom of my heart for finding the love I carried to heavy to accept, while I obviously thought it was so unfair, and to this day, I still think it was.

But now, a few years have passed, and my perception has evolved, and even if I don't think I'll ever be able to forgive them for what they did to me, I'm not angry, nor sad, nor frustrated anymore. Because these people are always on the run, trying to escape who they really are, because deep down, they have no sense of self, and that's why they don't know how to behave. I think that in the end, people like Jiho (or Cirrus from litc quite literally) always have to twist the truth, because as people who have never received love, they don't know how to give or receive any, which leads to this kind of destructive relationships, as much for themselves as it is for their partners. He's quite hard to understand, I take that, because even I am not sure whether I understand him fully, nor if I understand/ood why my ex partner was this way either. Sometimes, I just think it's not possible to understand people completely when we don't have the same background, and that doesn't mean we should crucify them for it. Yes, he's toxic, but after all, the person he hurts the most even now seems to be himself, always walking on eggshells, having to rely on mindless sex because he feels like he has nothing else to give... Well, I just can't but feel more sadness than anger.

As for Yujun, I feel like a lot of people idealize him, simply because he's not as toxic, or at least, not as destructive as Jiho is. But I don't think that should be the case, because this overwhelming love leading to dependency is also a poison to a healthy relationship, which is something people usually don't realize when they're going through their first relationship, since feelings tend to consume you whole. But after some time, people usually learn from it, when he didn't. He said it himself, they spent one year together, and six apart, yet he fell right into his arms the second he showed up. Why? Because he's lacking independency, and a sense of self in his own way as well, since his whole happiness has been based solely on a relationship that was bound to fall apart from the start. In this case, he's more the victim than the tormentor, but with a partner who had been more stable than Jiho, it's very likely the roles would have been reversed. He's flawed, and short-tempered too, nor is able to contain his urges, which is understandable to some extent, but that doesn't excuse everything either.

To sum it up, I just think the reason why a lot of people don't like the story is because it's frustrating, but it is in a way that it is realistic (to some extent, since it's still a fiction of course), and obviously, not a lot of people are ready to question the complexity of a character's personality, nor explore how easily someone can get messed up all because of one other person, since it's quite scary to think about.

By the way, since English isn't my first language, I'm sorry if some of my sentences seem weird, I did my best to make myself clear lolol