NO MATTER HOW MANY TIMES IT TAKES

On his way home from picking up a matching set of rings for himself and his lover, Fuji Takahiro is hit by a car. The following amnesia degrades his live-in lover Kotou Tarou to a mere flatmate, and a series of misunderstandings threatens to tear the couple apart. Tossed around by desperation and confusion, can Tarou and Takahiro rebuild their once blissful relationship? — Description from AniList community (anilist.co).