Poly Question

So, polyamorous people. I knew I'd have questions, and here is the first one I could use some help with.

Last night I took Grey (my boyfriend, whom I introduced a few posts ago) to one of my favorite restaurants. Chris and I eat there a lot, and the staff knows both of us, but especially Chris since he's in the business. Grey and I were sitting at our table holding hands as we looked at the menu. The maitre d' (who hadn't seated us, but came in a little later) started to greet me, then looked aback and gave me what I at least imagined was a cold stare.

I managed to say hello to him later, in hopes that he would see I was being open about the whole thing, but ... how do you handle situations like this with the maximum respect for everyone involved? I don't want to go around explaining "Oh, we're poly now" to every casual acquaintance who sees me with Grey, and they probably don't really want to hear about it anyway. But I also don't want to look as if I'm sneaking around on Chris; the idea is repellent to me. I don't particularly care what random people think of me, but I do care if they think Chris is being hurt or disrespected when he isn't.

I did briefly try to explain our new relationship status to one person who saw me out with Grey, but that person is a friend, not an acquaintance, and we were in a noisy bar and I'm not sure he got it anyway. At least he's gay and possibly acquainted with such things (though I know this is by no means a given).

Input is much appreciated.