Frankly I feel Hwan treated Jian better when they first started out as sexual partners.. now he keeps humiliating and belittling Jian every chance he gets..
I feel like the addition of having lost his memories and everyone trying to convince him of something so opposite of his current beliefs that it just makes him react more aggressively than he ever would have as their relationship built naturally the first time. He went through a whole growth process that got chopped at the root and isn't really being given the time or space to grow again. Not at all an excuse for the way he's acting, of course. It just makes sense that someone who hated omegas would be reacting so aggressively to being told you aren't who you think you are and you've got two different groups telling you who you actually are.
idc if hwan was the bestest partner jian could have ever had or if they were lovey-dovey couple in the past, but present hwan pissed me off so much I hope jian tired of his jerkass and left him for good