Kudos to you for being open. I've had amazing and memorable threesome, foursome and moresome experiences.

I suppose the cardinal rule is to choose a non-friend. I have seen that rule broken a number of times, but only by people who are all very open, have excellent communication skills and are well-versed in the politics of these sorts of things. If it's a new venture for you both, a neutral stranger or semi-stranger is probably ideal.

Usually then, it's a matter of finding said semi-stranger. I've typically found like-minded people at like-minded people events - like sex parties, workshops - but occasionally people luck out with online ads. Or in the supermarket.

Know your boundaries beforehand and talk about what you are both comfortable with. The experience ought to bring you closer, not create more distance, so you want to do whatever it takes to stay connected during it. Talk about it after and debrief (if you need to). These experiences can be amazing to deepen a relationship and I think the key to that is communicating whatever comes up for you along the way.

- Kasia