I recommend to read:
https://www.mangago.zone/home/mangatopic/10526356/
I just thought you misread some crucial parts because the whole story was about Joowon's and Haesoo's journey to be better people and to have the courage to finally be together. That was the whole point. Both of them hurt each other, their family circumstances twisted and impacted their relationship but although they've faced many obstacles, meet new people, they've never stopped loving each other.
Joowon bought the ring long before their infamous break up at the hotel... So like I have a feeling you mixed many parts and looked at the story through the typical trope "evil ex, main character - damsel in distress and second lead prince charming" but it was much,much more complicated than that.
I read this because I took a Yaoi character test and it said I'm Haesoo hahaha. The art style is so beautiful and the characters are so pretty. Their dead eyes makes my heart flutter. That being said, this is one of the worst stories I have ever read . What a waste of time. Haesoo went through ALL that , just to get back with his step brother again?! Who treated him like shit and would always leave him confused, would never confirm about their relationship because it would inconvenience his work all the while getting jealous and possessive when Haesoo meets other people ,and ONLY realises his feelings when Haesoo was about to finally move on?! Such a disappointment