I know there are fans who like the idea of a Xena/Ares/Gabrielle "menage a trois" where Xena is in a sexual/romantic relationship with both Gabrielle and Ares -- not "cheating" but a menage a trois with mutual knowledge and consent. (With or without a Gab/Ares component .)
Leaving aside fanfiction with this kind of scenario, do you think it's something that may have actually happened on the show? Or possibly after FIN if Xena came back from the dead? (Post-FIN scenarios aren't exactly canon, but they don't contradict the canon either.)
I mean, considering that both subtexters and shippers commonly "fill in the blanks" for what happens offscreen, why shouldn't bitexters/tritexters do the same? Most subtexters think that Xena and Gabrielle were in a sexual relationship by the end of the show, and a sizable minority of shippers think the same is true of Xena and Ares .... so, why not all three of them?
There are plenty of possibilities here. You could believe that Xena and Gabrielle are a couple since S2 and Xena and Ares are in an on-and-off relationship starting with, maybe, Ten Little Warlords (maybe breaking off after Sacrifice II, then possibly resuming in S6). You could believe that Xena and Gabrielle have been involved "like that" since S2, 3, or 4, and then Xena becomes involved with Ares in S6 (either when he's mortal -- say, between Coming Home and Old Ares -- or when he's a god again, after POV). Or that Xena becomes involved with Ares in S6 and her relationship with Gabrielle becomes sexual after that (say, after WFC). Or that one or both of the relationships start(s) after Xena returns from the dead after A Friend in Need.
So ... what's your scenario? Are there "X/A/G subtext" moments on the show that you would see as indicating that such a relationship exists? And what kind of a relationship do you think it is? Are both halves of the triangle equal, or is it understood that one of the relationships exists "on the side"?
Let your imagination run free!