Custom Tav is considered an Origin. The custom origin.
The confusion arouse when some addled forum member read too much into this
Romantic Alchemy – Yes, Origin Characters Can Find Love Without You
Even if you fail to connect with some of your companions on a romantic level, that doesn't dash their chances of finding love in Baldur’s Gate. Origin characters can romance other Origins so long as they’re not the primary character controlled by the player.
This was quickly redacted (not from the emailed version though) and replaced with the "least romantic way" of puting it. If they'd put it in terms of the player, instead of the Origin, I don't think we'd have to clarify further.
