Well, my best friend and her husband are swingers. Frankly I'm just as comfortable in a group of their alternate lifestyle friends as I am with friends of any of the other members of our D&D group. Often I am more comfortable with the alternate lifers because they have fewer hangups and tend to be very accepting of, and respectful towards, others. The parties can get pretty wild, too.

I'm very sure my best friend and her husband have not tried to "recruit" anyone from the group to their lifestyle. Though they did meet someone at one of their lifestyle parties who plays D&D, and he will be joining our group shortly. Swingers are no worse, in general, than any other group, including gamers.
Reminds me of a story. About twenty years ago, I had a regular Saturday night game at the house of another couple. One of the group members was Assistant Manager of the local Pizza Hut, so he would always show up shortly after midnight with fresh pizza which would keep us going until dawn. One night the husband of the couple was at the end of the table with his wife on his right and my buddy on his left. During a momentary break in the action, the husband got up to go make some tea. His wife got a funny look on her face and asked "How did you do that? Haven't I been playing footsie with you for the last half hour?" My buddy turned bright red, smiled sheepishly and said, "No, that was me." The whole group roared with laughter and we had to take a break before we could get back to playing again.
-Dave