TWhy do you think people act like that about the cheating vs. poly admission? What are your experiences with it? Have you ever lied and said you were cheating just to get some action? (DH wouldn't go that route, just curious about the experience of others.) If so, how did it end up?
Very entertaining and humorous thread!
But to visit the main topic I can answer this question from a non-poly viewpoint because I have never been in a poly relationship... but I have dated married men in the past who were cheating.
The reason I dated married men: (and more than one at a time) was that I could have my needs met and also maintain my autonomy. (So I am thinking... is autonomy the the right word?)
Autonomy: Dictionary.com: independence or freedom, as of the will or one's actions: the autonomy of the individual.
Yep its the right word.
To continue: Why date more than one married man at a time?
1. Because a married man usually did not have enough free time to spend with me.
2. At the time, I was not interested in getting married.
3. I liked the variety.
Back to the O.P.'s question.
If I had met a married man who made it a point to say that he was polyamorus, first I would ask him what that meant. (At that time they simply said they were in an "open marriage." The term Polyamory had not been common or used then.
The reason I would not have been interested in that then, is because "open marriage" often translated as "we are swingers" or "wife swappers" and I was not looking for that, not into group sex or orgies or a same sex relationship.
I have changed a lot since then. I eventually stopped dating married men because I had no respect for their dishonesty. At that point if a married man would ask me out, I would tell them, "only if its okay with your wife."
Today, if I met a married man who wanted to date me and he said his wife approved of him seeing other women, I might want to meet his wife to confirm that. (But not because I am interested in a threesome, or in his wife as a sexual partner.)