Why do you have to say ANYTHING for goodness sakes?
You are doing this out of emotion, not out of strategy.
And this strategy isn't just to save the marriage it also allows it to end with some dignity.
Going to HER now and saying "I'm done" isnt' going to help save your marriage and it isn't a dignified way to end a marriage either.
You are emotional right now and thrashing about... Don't do ANYTHING while you are in this state of mind... ESPECIALLY confront your darn wife with "I'm done"