Nudist(2003)

Nudist.

Senou Tsukasa is a baseball coach at a high school. He's never been able to forget Kamishiro Shuuichi, his high school boyfriend, even the student he's seeing now resembles Shuuichi. But the affair is discovered and Senou is fired. Now he's just drifting through life, until he meets Shuuichi again...

(Source: The Evil Empire.net)