Mimei no Inu

Shunya, the owner of a night-time brothel, stumbles upon Aoi, the "stupid dog" he had as a child, engaging in "sugar dating." Furthermore, he learns that Aoi had been having sex with the man who arranged the sugar dating. Despite having abandoned Aoi once before, his anger and frustration at him being taken advantage of leads him to have sex with him. Seeing that Aoi has no family, he takes him from his hometown and "keeps" him at his escort service.

Unaware of his true feelings towards Aoi, who works tirelessly and misguidedly for his sake, a twisted codependent relationship continues...? A maniacal, egoistic love story between a pet owner and his pet dog.
[via chill chill]