
Based on the novel, it's because suhan grew up without parents. And when his father finally showed up, the father ended up saving Yoonsung from a house fire. Making Suhan jealous because his father showed up for a kid he didn't even know instead of his own. Aside from that, suhan was jealous of Yoonsung's life since he's rich and has a loving parents who supports him. He dislikes the fact that yoonsung have the life he wanted. Suhan was kind of "toxic" before the amnesia. He only married Yoonsung because his parents helped Suhan finish his studies. That's basically the reason. If you read the novel, there's more depth and you'll emphatize with both the characters despite them being flawed (well, they're humans after all)

Based on the novel, it's because suhan grew up without parents. And when his father finally showed up, the father ended up saving Yoonsung from a house fire; making Suhan jealous because his father risked his life for a kid he didn't even know (there's more to this part of the story but I don't wanna spoil). Aside from that, suhan was jealous of Yoonsung's life since he's rich and has a loving parents who supports him. He dislikes the fact that yoonsung have the life he wanted. Suhan was kind of "toxic" before the amnesia. He only married Yoonsung because his parents helped him finish his studies. That's basically the reason. If you read the novel, there's more depth and you'll empathize with both the characters despite them being flawed (well, they're humans after all)

yeah, we'll most likely get a flashback of it (I think it will happen before Suhan get his memories back but ot's gonna be a long way). You'll hate and love suhan's characters during those times. When I say he's kind of toxic, he really is (he even had an affair with the chef from the restaurant, well, that's how they imply it).
Anyone who is willing to answer my questions, I would be very grateful.I just have one question, when Uke remembers everything again, will he act the same way he used to treat Seme?