I urge you to get advice from a professional counselor before telling your wife. It seems like the popular opinion on here is to come clean immediately. But I think it would be very benifical to you and your wife to get some professional guideance first.
How you tell her and what you say when you tell her will stay with her for a long time.
can't, that "popular opinion" you see here is straight from DR. Willard HARLEY, a "professional" psychologist. John does not need a counselor to tell his wife the truth. He probably needs professional guidance to recover, but there is no hope of that happening until the truth comes out. Here is Dr. Harley's [a "professional"]
educated opinion about telling the spouse the truth. Never does he say one needs to get 'professional advice" to do so:
Dr. Harley: "From my perspective, honesty is part of the solution to infidelity, and so I'll take honesty for whatever reason, even if it's to relieve a feeling of guilt and depression. The revelation of an affair is very hard on an unsuspecting spouse, of course, but at the same time,
it's the first step toward marital reconciliation. Most unfaithful spouses know that their affair is one of the most heartless acts they could ever inflict on their spouse. So one of their reasons to be dishonest is to protect their spouse from emotional pain. "Why add insult to injury," they reason. "What I did was wrong, but why put my spouse through needless pain by revealing this thoughtless act?" As is the case with bank robbers and murderers, unfaithful spouses don't think they will ever be discovered, and so they don't expect their unfaithfulness to hurt their spouse.
But I am one of the very few that advocate the revelation of affairs at all costs, even when the wayward spouse has no feelings of guilt or depression to overcome. I believe that honesty is so essential to the success of marriage, that hiding past infidelity makes a marriage dishonest, preventing emotional closeness and intimacy. It isn't honesty that causes the pain, it's the affair. Honesty is simply revealing truth to the victim. Those who advocate dishonesty regarding infidelity assume that the truth will cause such irreparable harm, that it's in the best interest of a victimized spouse to go through life with the illusion of fidelity."
Coping with Infidelity: Part 2
How Should Affairs End?