
People forget that the characters are humans so they can make mistakes, too. In the first place it was Natsuki aka the guy who was cheating who want there relationship back.
Natsuki didn't fight back nor stayed away after all that violence. In fact, I think that he was glad that he was punished but at the same time he was sorry for triggering his partner's violence when he saw him cry who clearly wasn't happy for what he has done.
The next chapter is pretty realistic, too. You can't repair that relationship after all that toxicity.

its not like arata was happy he did it, he was pushed to the limit and i find it normal if his impulse was to be violent. because guess what? all three of them are flawed and its not like arata should act like he is the perfect human being capable of forgiving a cheating partner with no consequences. Am I happy he did it? No, of course not. But I understand his motivations (and he is the only character whose motivation i understand so my heart reaches out to him)

So for you when a woman or a guy is beeing beaten after cheating it's actually his fault ? You can have anger I understand that but you have no right to rise your hand and the fact that he cried or I don't know what after is not an excuse ! I think that after beating him he actually have more to be forgiven about !
Violence has and will never be a proof of love ...( ̄へ ̄)

You're putting words into that person's mouth. Imagine a police detective trying to understand a suspect's motive or when someone's wife gets killed and the husband plotted revenge that ended up killing someone who also has a family. You can sympathize but that doesn't mean one approves of it.
Life complex and not one dimensional.

Well you are comparing to thing totally diferent ...
But I'm still maintaining what I said, if in your exemple the policeman understand it means that if he does't have to put him in prison then he would not do it and so does aprove deap down ... Also if he was in the same situation hwill maybe do the same and so same : it means he aprove ...
y'know, i don't condone violence but i do understand where arata is coming from and my heart reaches out to him. its not like he is normally a violent or an abusive person. He was a good person but good people have their limits too. Na-chan's physical bruises would heal but the emotional scarring he left arata may not. :( arata come here, i'll give you a big hug.