Physical danger aside (and I agree with the other posters that you need to get out of that situation) I have encountered this same thing with my wife. She was/is *furious* with me that I invaded her privacy. She blames me and my snooping and what she calls my need to control for all the problems in our marriage. She claims that my snooping on her was an equivalent or worse betrayal as her affair!!! Of course it is all justfication for them to feel better about the bad choices they have made. I contributed to the marriage issues (we all do!) but it is completely wrong to blame her affair on my snooping. Her affair was her choice, not mine.
I saw an interesting perspective on the right to privacy recently that goes like this: people absolutely have a right to privacy for all issues that do not effect the marriage and the other partner. It is without a doubt in my mind that an affair certainly effects the partner, therefore anything that the LBS has to do to find out is fair game (in my opinion). My suggestion - worry more about your safety and the well-being of your children than whether you violated a trust that was already shattered by your husband.
As an aside, now that I absolutely know about the affair my need to snoop has completely evaporated. It amazes me that my wife can deny her affair even in the face of very incriminating evidence, but I believe that is the "fog effect" we hear about.
