i don't think it helps much to try and convince him that he's just confused or doesn't actually know how he feels, cus he knows himself better than anyone else, and it'd be condescending and insensitive to say he just doesn't know any better, or that he'll "correct" himself eventually. if everyone in the relationship is aware and consenting, there's no reason why a relationship like this can't work. it's obviously not for everyone, and it's certainly not conventional, but i don't see why it wouldn't work out.
of course it's all just chemicals making you feel anyway right ??
also check out this vido (the more relevant bit starts at around 5:43)