I'm trying to figure what the bad thing you did is. Your posting's got me thinking about the men in my life (there used to be). Aren't all of us girls/women somehow programmed to not take action when it comes to attraction? Don't people sometimes just get high on something and just go ahead and kiss others? Because the tendency in your situation (married) is for you to think that you teased your guy friend, but I get the feeling this is not necessarily true.
You feel guilty both about being kissed by another man and about not telling your old man about it.
If it was a meaningless kiss (such things do exist, don't they) and you feel like you didn't kiss him back, then maybe you're being too hard on yourself, possibly for being an attractive person/woman. But it's out of guilt?! If you are attractive, you're not guilty. If you didn't kiss him back, your husband didn't need to know, because you're not guilty. Seriously.
And even if the kiss meant something... you are not guilty.
But if it happens again, maybe you should just keep it to yourself and not share it with your Christopher.

Love
Peace