So he is not in a relationship with the other guy... Ryuji
I hate to say it, but I think it's an affair. I mean, who's Ryuuji's uke, if it's not?
Ooooh! So this is also tied to the original story from "Not for Sale," Ryuuji's love story, which apparently has been licensed and is... unavailable... in scanlation :( Great.
http://www.mangago.me/read-manga/the_king_of_debt/an/the-king-of-debt-chapter-6.html/4/