Rob is right. I believe in snooping, when you're in the "evidence-gathering" phase, or when you're having to make difficult decisions about whether to go for custody, etc. But you've known what you know for a long time now (albeit you just got proof it's been going on LONGER than you thought.)
Print them and give them to a confidante for safekeeping. Looking at them daily will kill your spirit.
If you haven't already done so, I do think you need to enforce a boundary with your husband as to what he does from inside of YOUR home, presumably on a computer than is at least half yours?? You can't stop him from the incredibly foolish and selfish choice of deciding to have an affair, of course, but you can certainly enforce your own personal boundaries, and not enable it. If he crosses your boundary, let there be consequences.
