Responses

I think it's always been both. Like others have said they for sure have some sort of backstory, like (random common trope that would fit): Taeha was a lonely and abused child and Haesoo years ago was the first and only person to help him/show him kindness without any second motives, and that probably made him both have a crush on her and be obsessed. Then he probably grew up and started looking for her in order to persue a relationship with her but she was already married, so he studied the situation etc etc
Guys do you think he actually loves her? Like sometimes I feel maybe it’s just obsession or something but then it seems like he actually cares. What do you guys think?