Shitsuren Mania

from hochuuami : An ongoing series revolving around Atsuya, who is an "Unrequited Love Maniac" and the possible lovers he acquires. Prequel: Hatsukoi Moratorium inside Shotgun Marriage (Nakura x Atsuya) Vol.1: Shitsuren Mania (Unrequited Love Mania) Vol.2: Junnai Allergy (Allergy to Pure Love) Vol.3: Netsuai Complex (Ardent Love Complex) Vol.4: Dekiai Egoism (Enraptured Love) Vol.5: Katsubou Catharsis (Catharsis of the Love) Vol.6: Saiai Ambivalent (The Dearest is Anbivalent) includes characters from a few other mangas by the same author.