I'm feeling fortunate to be somewhat new right now, as I haven't had to bang my head against this yet. The way I see it - and it's massively simplistic because I tend to be 'orribly black and white - is this:

If I write a piece for an erotica publisher, then I default to M/M (and mostly D/s BDSM if we want a couple more labels for the pile). I don't have a problem with this classification because I come from fanfic, therefore all that has changed in my labeling is that I've swapped slash for M/M. *shrugs* Big, fat hairy deal.

If I insert a gay pairing into anything else I write - which will be predominantly fantasy fiction - then I treat it exactly the same as I would inserting a het couple. It's not the main thrust of the story - the plot/politics/big nasty gribbly is the prominent theme.

If my readers get their knickers in a twist about finding such a pairing in a book without having been warned, well, tough. Yelling and screaming hasn't happened yet (and I have done it in fanfic - I got a truckload of 'I don't usually like slash, but...' comments), but I suppose at some point it's inevitable.

I'm going to try hard to continue to think this way once my living depends on writing because, blunt and simple though it is, I think it's important.

Fingers crossed on that one.

*edited for stupid fat fingers on keyboard error*