Responses
Do we know how and why Taeha fell for Haesoo?
Not exactly. But we did see flashbacks of a badly abused teenage Taeha getting comforted by Haesoo.
We can assume that's how they met, and Taeha fell for Haesoo. Though it's not confirmed, we haven't seen their complete backstories yet.
So, Taeha has even controlled when and where Haesoo amd Minshit see each other again I love him, so meticulous.