I think I get it what really is happening with Keiichi. It's not because he lost interest for Shingo. It's just he just focus on the sex, and forget about the 'love' he usually does with him. So if there's no feeling (heart), there's no smell. Since he's too focus with his job, Shingo is trying very hard to not become a obstacle for him, even if it means being less and less with him. I believe Keichi asked his brother to keep an eye in Shingo already assuming he will have to leave. But knowing Shingo, off couse he will want to be alone. Now there's two options for Keiichi. And he will end up loosing something in both cases.
I think I get it what really is happening with Keiichi. It's not because he lost interest for Shingo. It's just he just focus on the sex, and forget about the 'love' he usually does with him. So if there's no feeling (heart), there's no smell. Since he's too focus with his job, Shingo is trying very hard to not become a obstacle for him, even if it means being less and less with him. I believe Keichi asked his brother to keep an eye in Shingo already assuming he will have to leave. But knowing Shingo, off couse he will want to be alone. Now there's two options for Keiichi. And he will end up loosing something in both cases.