Thank you all, people for the helpful responses.
From what I read on this topic and from what I observed so far, I think that it was a mistake to write in my ad in a nonswinger dating site that I was married and had permission. It seems to scare a lot of people away right off the bat. Maybe it is better to have it off and disclose it a bit later, after it is more clear that the other side is interested.
Fear is a symptom of ignorance. Knowledge is the cure.
Age and location seem to be the two most determining factors in the acceptance/rejection issue. In my parents day , interracial relationships were the most frowned upon. Times change and so do attitudes, but we still must be careful how to approach these subjects to other people. That said, the issue of adultery/cheating seems to have stood the test of time. The bottom line is that integrity in personal relationships is the single most important factor, and causes the most adverse reactions.
I think cheating is accepted more because it's easier than swinging or being openly non-monogamous. To be open requires the fearlessness to be honest about what you want and a willingness to go through the myriad of issues like jealousy and ego bruisings that come along with opening up.
Cheating requires that you just sneak off and fuck somebody.
Some where this topic took on a new life around honesty and judgement and a few other things.
People are people...very true. Cheating is in the news everyday. Just pick up the local copy of People on the way out of the store and the subject is on the cover of every issue. Who's cheated on who this week. It sells really well obviously.
The more something becomes a common thread of discussion it's loses it's shock value. Cheating has lost it's shock value years ago...swinging though I'm sure will be one of the next big ones as it rises in popularity.