I'm as pro-exposure as anyone here other than maybe Allen, but I don't believe in just exposing scorched-earth to everyone. OP's spouse, both immediate families (including adult children and possibly teen children of the affected family), employer (if they work together), plus maybe any "best friends" who may be in a position to exert some influence on the situation, IF you know they will be supportive of your marriage.
I also don't think there's anything wrong with telling your OWN best friend or two, if you feel you need a confidante, but I would ask them to be discreet.
Beyond that, I certainly wouldn't lie if anyone asked me directly, and I would TELL my wife (and I did), that "I have decided that I'm no longer willing to lie to cover up your affair." But I wouldn't expose to such a wide circle. Those folks aren't in that much of a position to exert positive influence anyway, and it only makes the reconciliation that much more difficult, in my opinion.
