Ai no Binzoko
Other names: 愛のびんぞこ。, Ai no Binzoko.
From Hoshikuzuu Scans: Detective Hishima’s lover is former colleague and detective, Enokizu. He is still sore over an unresolved incident that occurred 3 years ago that caused Enokizu to quit his job as a detective. The story of heart-throbbing, imperfect love.