hmmm

I want to analyze why Taekyung has changed his attitude toward Heeseo in the last few chapters. It's not that he had a personality change, and it's not Stockholm syndrome. In reality, his attitude changes after the hospital incident, when he sees that Heeseo was involved in the legal arrest of the purple-haired woman. I think one of the main reasons for Taekyung's discontent with Heeseo in season 2, was that he believed the blond man had committed murder. And he couldn't live with that.
Taekyung is a prosecutor, and he lets Heeseo get away with a lot of things, but he wouldn't tolerate murder.
Heeseo didn't murder anyone and so Taekyung became accepting of his feelings, and Heeseo's feelings.

Besides, we see how Taekyung himself accepts that he went to see a therapist not because he hated the young man who stabbed him, but because he missed him. He then admits to having remained celibate because he didn't want to be with anyone else and admits that what Heeseo says to him hurts him, hurts his heart. It's just that in season one, Taekyung was the adult and had to be responsible one. Being Heeseo's lover didn't seem right or proper, but he fell in love anyway.

I'm not saying it's healthy. Neither of them is mentally stable. Maybe that's why it's tagged as psychological.
That's my explanation.