Boku janakya Dame deshou?

Takatsu, an anesthesiologist, has been doing his daily work with Dr. Miyamura (a younger surgeon) as just a "good colleague". One day, Takatsu witnesses Dr. Miyamura's private life, which he thought was impeccable and therefore uninteresting, and invites him to bed out of curiosity......!

(Source: Gentosha, translated)

Note: The chapter count includes 1 extra.