I Was Possessed by Your Ex-Boyfriend

On the first day at his new job, Ji-Ung ends up falling in love at first sight with his immediate boss, Kim Sang-Ha. He vigilantly looks for a chance to get closer to him, but is disappointed when he hears that Sang-Ha is currently mourning his dead lover. Then one day, when Ji-Ung is driving drunk Sang-Ha home, he suddenly feels his body slipping away…? Goodness, how do you deal with the aftermath of having sex with someone while being possessed.

(Source: Bomtoon, translated)