We've been there, very recently in fact. Both of us are very into kissing, the other guy was as well, the other girl was not. Dunno if it's a general preference or she's just not into kissing me. For us it's not so important that we ask about it in advance, but it is important enough that we won't repeat with anyone with such a rule. And if it starts to happen too much then it just might become important enough for a pre-play rule. With this particular couple it didn't really matter, kissing was just one of several things we weren't really clicking on so we weren't going to be getting back together with them anyway. But if you're both into kissing as part of the action, why settle for a couple that isn't (both) into it? And speaking from the guys perspective, I don't really like my wife and him kissing not because I don't want her to get what I'm not getting but I don't want him to get what I'm not getting. Sure it sounds a little childish, sour grapes, whatever, but we like to play where we both feel good about things after. If the situation were reversed (though the few times it's happened it's always the girl with the kissing issue...no, my breath isn't bad!
) I would feel exactly the same way, as would she.