I don't think you want to snoop until you are ready for whatever you find, and have a good idea of how you will deal with it. Otherwise you will end up action out of emotion, and you will lose whatever benefit the extra knowledge gave you.
Spot on.
If you don't think you can handle finding a letter or email where he and the OW are talking about how great last night was, or making plans to get out of town for the weekend, then you should not go snooping.
At the same time, keep your eyes and ears open for evidence.
Me: 44, Wife: 39 M: 17 years T: 20 years Bomb on 08/25/09 1/13/10: MC started 1/28/10, 2/8/10: More bombs 8/28/10: Wife moved out No talk of D, no movement