Tonari no Megane-kun.

Minami has been living with Kuriko's family ever since his parents passed away when he was a child. Over the past fifteen years, things have stayed pretty much the same, but when Minami unintentionally reveals his "more than friendly" feelings for her, their relationship is changed irrevocably. This is a very funny, sweet story about two life-long friends who fall in love.

(Source: Storm in Heaven)

Included one-shot:
Volume 1: Koishii Hito