If you are planning on saving your M, even if he is having an A, then I would expose it anonymously, so as not to have yet another strike against you when you are trying to reconcile. But that's just me, I'm trying to get out of my B****y ways, so I wouldn't do it openly.
I disagree. "Strength and honor" should be your mantra, and there's nothing wrong with standing and fighting for your marriage. You don't announce it ahead of time, but once having exposed, you stand proudly and say "yes, I did that; yes, I knew you'd be angry, but I did it and EVERYTHING I've done to fight for our marriage and for our family."
The anonymous stuff is going to be found out anyway, and when it is, then you REALLY don't look like you're being honorable.