Oh, sweety. You have to keep in consideration that unless your wife supports you and truly loves you, you'll be the villain here. Can you imagine what she'll feel when you tell her such thing? She'll be destroyed and probably loathe you for life because of it. She may also feel she was "responsible" for it. I've personally seen cases of women who catch their husbands with other men in bed or otherwise... It really drives them, quite literally, crazy. I don't think you want such pain and confusion for her. You do owe her some honesty, though. Try and take her into counselling and from there, a more or less neutral ground, explain to her your situation, your feelings. That way both of you will have the help of a specialist and you can be freed from it all. Ultimately, it's your choice.
Good luck. We all make mistakes. Do remember that. *HUGS*