Perhaps cheaters don't have anything of value to contribute to the poly community, but the poly community may have plenty of value to contribute to their lives. Especially, as InquiringOne described, those who would like to move from deceptive-cheater status to open-and-honest-poly status, but they are not sure how. If anyone has the resources to help them, we do.
In my opinion, if you don't feel emotionally safe bringing up poly in the context of your marriage, then your marriage has a problem. You are not free to be unconditionally who you are around your spouse. That is not real love. Even if you never bring up poly and never cheat, this lack of unconditional love will show itself sooner or later and cause problems in your marriage. I myself had it easy, because I was already going through a divorce when I realized I was poly.
I think the real question is: Can we help cheaters become non-cheaters, and if so, how?
Independent polyperson seeking friendships, in which physical intimacy may or may not develop.
I do not wish to attach to any particular person. My love knows no limits.