I guess what's allowed evolves over time and with comfort levels. We talked a lot about boundaries before our first experience.. Started off just wanting girl on girl with boys watching. That evolved to OK with touching, to what about oral? OK, maybe. Full swap? Definitely not.
Actually in our first experience, we dived in head first and maybes become completely fine and now we're talking excitedly about full swapping when we get the chance.
Kissing is clearly a funny one. I'm not OK with it (Mr), I think Mrs would be. For me, even before I joined the scene I always drew a clear distinction between just sex with girls, and on one night stands often didn't kiss them. But for making love to someone I have feelings for it's very much a sensual part of it. So, to kiss another feels way more intimate and 'loving' than just pure, albeit naughty sex.
Also, I think it's nice to have something that's reserved for just us and if we do full swap, what's left?
So we will be, no kissing (the boys, girls together.. Anything goes). Also don't come in her mouth.. I want that just for me. Condoms are a must for health reasons but I can see myself being less bothered about a guy coming in my wife than kissing her.
Different strokes for different folks I guess and maybe some of those boundaries will drop away in time too. Time will tell and its going to be fun finding out! ?