1 I can relate to your situation as I am in the same one. I have not told anyone other than online and the secret is killing me. I want her to know what I am feeling. She knows something is wrong and has told me to put it on paper she also suggested a psychologist to talk with. She has no idea. I want to be free of the pain.
As for telling your wife make sure you know what you are doing and the possible consequences. I have thought through all of them.
I know one day I will tell her, just not yet. I will work through the emotions and its sites like these that really help a lot.