Kowarekake no Omocha

Shinobu left his large family to go live with Kengo as his playmate and companion to earn extra money once his father fell ill. Kengo takes advantage of Shinobu's position as his "toy", and when they are older he begins to have sex with him as well. Shinobu is afraid that Kengo will throw him away once his usefulness is over, proving that Kengo doesn't love him. Where will this relationship go as the boys go through high school?