I wouldn't worry too much about it - there is, quite honestly, someone for everyone. Being 30 pounds over ideal weight isn't going to stop you, and these days it's really more common than not (though I would encourage you to work on staying healthy). As Spoo said, being naked in front of other people can really serve as a motivator to get in shape.
In my experience, swingers are pretty much just a cross section of every day society. Go out in public (say, a grocery store) and look around - see the people around you? Imagine them naked. Substitute the checkout counter for a bar, switch the paper towel display out for a stripper pole, and get rid of anyone under 21 or so and you get an idea what the club looks like.
