I mean, it sounds like the "if you redecorate for me then we'll bang ok?" is entirely his idea, in this premise, so I don't think seduction utility needs to be a factor in the decorating decisions. So I'll probably just stick to good usable principles: keep traffic lanes clear, put light sources at or below eye level, maximize natural light, install bookshelves, get art that's by people he knows or personally relevant to him...