Mizuno Shinobu no Risou no Renai

Mizuno is a thirty-something office worker who is not good at real love and loves shoujo manga. While he is tormented by regret after spending the night with Meguro, a subordinate he has a crush on, under the influence of alcohol, Meguro casually proposes to them that they go out together...!?

(Source: Shinshokan, translated)