Maybe the reason it is so hard for single guys is because by tradition and definition swinging is about couples. Some swing clubs allow single guys on some nights to make money, but basically they allow singles to watch usually the exhibitionist couples that come those nights and many other swingers avoid.
There are very good reasons why couples like to share with other couples.
Yes there are some couples that enjoy a extra man once in a while but the supply of wantaparticipate single male is humongous. There does seem to be more interest in some cities for single males if the male is bi.
Back years ago when I led the Phoenix couples group, we ran ads and for every 10 couples that responded we had 100 single guys and maybe one single female (they often were doms looking for slave guys).
Out of frustration not being able to help single guys I got interested in sexwork which often is a far less expensive practical alternative than the disappontments of trying to be a single guy in swinging which again by definition is for couples.
Dave in Phoenix
Founder, Liberated Christians
http://www.libchrist.com and
Sexwork Resource Center
http://www.sexwork.com
LoveTouch & Therapeutic Touch Institute
http://www.lovetouch.info