Man I'm really, really sorry you're struggling right now. No doubt you are in a tough position and the revelation, although you more than likely suspected it, is nothing compared to actually knowing about it....I can't imagine how much of a kick in the stomach that all was to you.
That being said, let me just offer my quick .02 worth here. I believe that an open conversation with your W is critical here because what I see happening is a major passive-aggressive dance between you and your W. From your perspective, you're holding all of this in and its coming out in other ways, whether you think it is or not. She can sense it, she knows it. At some poing, this bottled up anxiety is going to bubble over and the next thing you know you'll be embroiled in a major argument over who forgot to put the butter away after dinner.
Now notice, the distinction between a conversation and a confrontation. Nothing is going to get resolved by confronting her with all the proof and basically treating her like a hostile witness on cross-examination....the expectation there is that you will prove your moral superiority and she will bend to you will. Not likely to happen.
Instead, report YOUR concerns to her. Let her know that you have found out, that, obviously, you are hurt by it, and further that there is a fear for your health and, as a result, you are now anxious about any STD's you may have contracted. Don't pull the moral superiority out here, just be straight forward.
This is about the best advice I can give you right now. Holding something like this is only going to cause you greater anxiety and create more issues.
In any event, the best of luck to you and I sincerely hope your day gets better.
Rob
"Achieve success, but without vanity; Achieve success, but without aggression; Achieve success, but without gain; Achieve success, but without force." Lao Tzu
