Responses
thats certainly not love. He's simply obsessed and infatuated. His emotions have nowhere else to go so hes directing it all towards Taekyung, be it anger confusion resentment fears insecurities lust etc. bottom line is that he's mentally unstable, and by giving in Taekyung is unfortunately further enabling his behavioral and mental issues.
While there's no doubt Heeseo is in love with Tae-kyung, he clearly has underlying mental issues compounded by the obsession and which is sadly being overlooked by Tae-kyung. Sadly his obsession will consequently fuel an eventual psychotic breakdown that both will suffer from.