I haven't and don't plan on it, nor would I ask or expect my wife to take one for the team either.
But attraction is a funny thing. It is not a black and white thing. It is more shades of gray along a spectrum, from hell no on one end, to hell yes on the other end. We have met some couples that, unless they meet a hell yes, then it is a no go. I suspect in some cases these people are really not in the lifestyle for anything more than the social aspect, SwINO's - Swingers In Name Only, if you will. After all it is too easy to find imperfections be it physical or personality. I am married to the most perfect woman I know and she is not perfect (no am I), and I don't expect her to be. So why on earth would I expect that in anyone else.
The example I am about use is for illustration purposes only, we are no where near this precise or scientific. It is just a numerical way of explaining our thought process.
On a scale from 1 to 100, a 1 being "not if they were the last person on earth," 50 being "Maybe, it could go either way," and 100 being "This would fulfill my wildest fantasies."
The closer my wife gets to finding a 100 the further from 100 I am willing to go, but there is a limit. At some point I would just have to say it isn't going to happen. Is that limit 50? Is it lower? I don't know because we have never been tested. Usually we agree and if one seems to have little interest the other will move on. But then again neither of us have ever found some one that would be a 100. IF either of us show only marginal interest we just keep looking. Our encounters are usually fall somewhere along the lines of "there is something about them that turns me on," let's call that a 65, to "I am REALLY interested in pursuing this," let's call that an 85. I don't consider that as taking one for the team.
But I am certainly willing to at least entertain the idea of a "maybe" if my wife finds that 90 to 100 kind of guy.