Geu Namjaui Bam

Chi-Young, whose girlfriend who whispered that she loved him suddenly disappears one day and he is left with a huge debt. He receives a suspicious offer from a mysterious man saying that he will be paid 100 million won if he works for 6 months, and he becomes the home nurse for Ui-Hyeon, who was a classmate from orphanage when he was young. Just as Chi-Young's heart gradually opens up due to Ui-Hyeon's affectionate attitude, Ul-Hyeon barges into his room every night to have sex with him, and it's killing him...

"He pretended to be innocent, but he's a total pervert."

(Source: Mr.Blue, translated)

Note: Chapter count includes two Vacation side story chapters.