Ai no Kusabi.

On planet Amoi, a great society has developed, creating a computerized city called Tanagura, ruled by a supercomputer, Jupiter. The populace is almost entirely male and is based on hair color; light-haired men, "blondies", are the elites, and dark-haired are the bottom of society, often known as "mongrels". Blondies keep young boys as "pets" for a few years to perform sexual actions for the Blondie's voyeurism entertainment. Blondies aren't supposed to keep pets for long or interact sexually with pets, but one blondie named Iason Mink has kept a pet named Riki for years and is rumored to sleep with him. Iason refuses to let go of Riki, even with Jupiter's disapproval. Iason is obsessed with keeping Riki, and Riki doesn't know what to do; fight against him or surrender to him, nor what to do about his old friend/lover Guy and their gang.