Little Butterfly(2001)

Little Butterfly

Kojima seeks to befriend the class outcast, and soon learns of Nakahara's troubled family life - of his uncaring, abusive father and mentally unstable mother. As Kojima yearns to somehow comfort Nakahara, he gradually becomes aware that his feelings for the other boy arise from more than mere sympathy. When Nakahara declares his own romantic feelings for Kojima, their relationship becomes one of sexual exploration as they face their first steps into adulthood together.

(Source: DMP)

Note: includes four extra chapters.