Yeonhwa and Dahye had a very toxic relationship since highschool, but they were still very atracted to each other. And I think they loved each other to an extent where they were abusive to one another. Even when Dahye wasn't anymore, she still couldn't understand and accept Yeonhwa's compulsive and toxic qualities. I guess, the ending is satisfying and okay in a way since they both ended up finishing their relationship. And Yeonhwa ended it with Dahye because she wanted her to be happy and didn't want to be toxic to her. I think Yeonhwa loved both Dahye and Yeon-young which makes sense since she chose to let Dahye go, and when she had no where else to go, she remembered Yeon-young but still decided not to go back to her. I, honestly, commend the author for thinking up such a complex storyline and characters. Indeed, humans are as complex as the characters the author came up with. Much success to the author in future endeavours.
Literally, men as the center of the world with a harem of girls is the worst ever storyline in ANY genre. Get rid of the Yuri tag, and gtfo of here!