I think you sound like a reasonable and remorseful man. It will destroy your wife to know AND the relationship you two value. Some lessons in life teach us. They are painful. But I'd look at this as a lesson. Drinking to excess like that is dangerous. And no sexual escapade is worth hurting your wife or your relationship. I would never tell her. Make it up to her by being ever so grateful for her and be the best partner you can for eternity. :>) And IF you feel the guilt is sucking you in and you need to tell . . . get a therapist and work through it. You sound like you have suffered enough and should focus on moving forward to me but know it can be hard sometimes. Hang in there.
Some things you just have to live with. I think it's good you didn't tell your wife, since you obviously don't intend to do anything like that again.
I see it from both angles. It seems reasonable not to tell her as it was quite clearly a mistake but as I myself am in a committed relationship, I do feel I would want to know if my partner had sex with another person. I also feel it could eat at you to have this dark secret for the rest of your relationship. By bottling it up are you simply reminded of the guilt you feel every day because you’re not able to address it?
You do the decent thing mate and you tell her the truth. You know that being lied too is more painful than the act itself. Atleast youre showing your remorse by being honest. Aslong as someone told me the truth even after years id still be grateful. Its awful that people condone lying to your spouses to keep the peace. Whatever happened to the ugly truth no matter what? Hopefully your guilt will disappear when you tell her. Poor gal. If not i hope someone tells her for you.