I'm having this issue as well, for the fandom X-Factor (Comics). The relationship is Rahne Sinclair/Julio Richter/Shatterstar, but - since it's not canonical (at least, not on the AO3; its canonicity in the comics themselves is another story altogether :-P) - it won't let me add it.
(no subject)
Date: 2012-10-06 11:24 pm (UTC)