Because some of the folks have had a great deal of success ending their spouses affair by outing the affair. What may not have told you is they haven't repaired their marriage. It is rarely part of the repair the marriage/bring more love into your marriage.
Don't you want your wife to really really love you? I know you do. I know you feel hopeless and want to cling to ANYTHING, because these guys so strongly pursuade you to man up and do that...and Michele herself isn't on this board.
If you out her, you will need a very strong arsenal of love to bring her back.
Why not protect her, find a way to get her back...because she's into you. I know you are worthy. I KNOW you can do this!
YOU are the man. You have loved her longer and better than anyone, and instincively, YOU know what has gone wrong. YOU ARE MAN ENOUGH to fix it without ratting her out.