Saki ni Ochita no wa

After getting fired from his part-time job, Arashi Hayakawa is on the hunt for his next gig. A friend recommends him for a position as a housekeeper, but there's a catch: the employer is Chikage Yuzuki, his high school classmate, with whom he never got along. Nervous but determined, Arashi begins working for Yuzuki. His former classmate is just as arrogant as ever, yet occasional glimpses of his softer side leave Arashi completely flustered. Then, one day in Yuzuki's room, Arashi makes a shocking discovery: a photo of himself with some adult toys...

(Source: DLSite, translated)