Sensei(2009)

Sensei, Kiss Shite Ii desu ka?

Sensei rejected Fuji when Fuji confessed to him on graduation day. After that, Fuji always visited sensei and they still went out together. Sensei realized his feelings gradually and hoped to start afresh with Fuji. However, Fuji couldn’t believe it. But when Sensei’s ex-lover, Namiki, came back and wanted to reconcile with Sensei, both Sensei and Fuji found that they could no longer hide their own feelings anymore.
(from Attractive Fascinante)