Demisexuality and emotional attachments go hand in hand. You can never find demisexuals getting into random hookups and one night stands as it is all about establishing an emotional connection before having a sexual connection with a particular person. Some of us don't identify ourselves as demisexuals because we think that's completely a different orientation but indeed it's one of the sub orientations. Yes, you can be gay and demisexual too, if you only feel comfortable having sexual affair with a person whom you have already made an emotional connection!
But do you think to have just an emotional connection can make you end up having a demisexual partner in your bed? In that case, many fools would try portraying their perverse nature by spilling the three magical words on demisexual people for fuck's sake. If you think demisexuals are dumb enough to detect your desperate behavior and your fake trials of having an emotional connection, then you prove yourselves as dumb. Demisexuality is all about emotional connection, but one must build an emotional intimacy first to have further commitments including sexual connections!