He does like him

I think Jaemin does like Taeyoon but his feelings of love have become so warped since he's been obsessing over Taeyoon for so long that he no longer truly understands himself or what he's feeling, but all he does know is that Taeyoon has to stay by his side. Which, that level of possessiveness obviously stems from loving Taeyoon but being unwilling to admit it since those feelings got him so hurt in the past before (also Taeyoon never confessed). Not justifying Jaemin's actions btw but it places us at an interesting point for s2 to jump off of if we're going to be getting into the nitty gritty of his psychology and how it affects their dynamic moving forward