In the side stories, we see his reasoning that his feelings aren’t pure or of the nature of normalcy that Hamin previously stated (in the early chapters) he desperately wanted and struggled for. He saw his desire to “have” as heavy and not something he would profess to Hamin who he believes to reject that absurdity..
So I think it’s a bit both.. he loves so much to have him and he has to have him because he desires and wants him..
Also when they were kids we see that Hamin bubbly personality brought him respite from the orphanage and even at the season finale he threw a tantrum because Hamin took a stabbing for him
It's not love obviously, it's obsession. It's the only way a sociopath can 'love'. People often seem to forget that he IS a murderer, someone with extremely low empathy. He cares about Hamin in his own way, a way which doesn't fit with our definition of love which is connected to our ability to empathize.
He is in love but on his own way which is brutal, possessive and manipulative. After all he has gone through in life it's a wonder how he is not just on pair with the other shitty characters of the story but still has a grain of decency in dealing with the MC. And somehow the reason and answer for this is a somewhat roundabout way of "love" for the MC. Everything that has pushed him in his life was to be able to stand besides MC despite him being trash both as a human as well as socially. Let's never forget that MC comes from a criminal family as well, so in order to "get him" he has no choice given his extraction but to conquer the upper ranks so that he can reclaim MC as his as well as to be able to protect him. It's truly a bittersweet love story, but the only story you can have in that kind of environment. It does make kinda sense when you think about it but I don't know if I managed to explain it properly.
I'm not sure if I missed something in this story, but I feel like Sehyuk isn't in love with the MC? Like, he definitely wants to possess him very much, but it's not love, I feel like he doesn't care about him or his feelings, etc.
Am I the only one who feels this way T-T