While I was still in the talk-the-wife-into-it stage, I visited an local swing club a few times as a single guy. (It wasn't cheap)
I'm not going to say my experiences were normal. Your miles may vary.
But here's what I experienced:
First time there I struck up a conversation with a thick brunette who thought I was nice and agreed to show me the ropes.
First time I saw the playrooms it was an instant turn-on. The scene included lots of black guys running trains on the ladies. (I had only seen a handful of black guys out in the club area, and no wonder -- they were all in the playrooms, getting it on).
The next couple of times I went to the club (again, alone), I coordinated with my new friend and sorta hung around with her crowd in the main club area, around the dance floor. I liked the energy of the place. Lots of sexy outfits. Bodies of all types. Nobody seemed embarrassed about anything, which was great.
But what I experienced was that people generally hung around with their own little groups. I tried to talk to some random people, and most of the time the husband/boyfriend would either immediately put his arm tightly around his woman's waist or he'd half-turn his shoulder to me, as if he didn't care to have his lady talk to a stranger. Weird.
If you can make friends with your own group, on the other hand, anything goes. There's a good chance you'll be able to fuck someone in the group (if not several) during the evening. Also, the ladies in the group are sometimes the ones that introduce you to women in other groups. Husbands don't seem to mind their ladies talking to other women.
Again, I'm not saying my experiences at the swing club were the norm. But this is how mine went.