The Kept Man of the Princess Knight, Vol. 1 (manga)

The labyrinth calls, and is answered by adventurers, profiteers, and anyone looking to make a quick buck. And in this town inhabited by the dregs of society live a man, and the woman who owns him. Arwen, the Princess knight with lofty dreams of restoring her homeland--and Matthew, the town drunk. As Arwen challenges the labyrinth, Matthew spends his days in taverns and brothels living off the money he gets from her. But the town laughingstock has a side that no one knows about. In service of Arwen, Matthew would do anything--no matter how dirty he might get.