Oh, is it the usual problem?

As a demi myself I guess he's probably demi as wellヾ(❀╹◡╹)ﾉ~

*nods* I think the main problem is that Japanese people don't seem to fully recognize these differences, because I swear that most of the characters in these stories are either demi or pan.

But demisexual means that you only feel sexually attracted to people whom you have a strong emotional bond with, but in a lot of mangas the men are playboys or at least they do feel sexually attracted to people they've dated (although I agree they usually only actually fall in love with one person), so I don't think the characters (or at least the semes) in yaoi can be described as demi

Well, there's yaoi and yaoi. I tend to think about this with the long(er)-running ones, where you can actually see more inter/intrapersonal development. But I agree that many -if not most- seme in yaoi lack emotional complexity. I think some of my favorite ones, like Blue Sky Complex, have this kind of seme. Then again, apparently now pan falls under the category of bi, and demi under ace, so sexuality is fluid indeed! ^^

Oh, then I agree about there being demis on longer mangas because you're right, they do spend more time forming a bond than going straight to sex like most yaois