I am very glad you feel so guilty. That is the Holy Spirit speaking, and you are listening. Have you knelt and confessed to God, begging His forgiveness? That's your first step, and He promised to cleanse you when you repent. Read Psalm 51, King David's prayer after he committed both adultery and murder. God forgave him, and He will forgive you. See also I John 1:9. But you also sinned against your wife, and that will be difficult. While it will hurt her to know, if you keep this to yourself, it will damage your relationship. She will sense something wrong, and you will be withholding yourself from her. When you tell her, I suggest you prepare her somewhat. Let her know you have something terrible to confess to her, and not just blurt it out. Be sure to emphasize that you love her and there is no lack in her that led you to this. Beg her forgiveness, and then give her time to process this. It will surely take her a while, first to take it in, and then to get over the shock, and finally to forgive you and trust you again. You might offer to set up some ways for her to keep track of you, as reassurance that you are now behaving yourself. I also suggest some introspection to become aware of why this temptation was so powerful. It sounds to me that it was your ego, not sexual desire, that was so vulnerable. Is there a wise counselor at your church, or a Christian counseling service in your town? If not, you can have a free consultation with a licensed counselor at Focus on the Family, 855-382-5433. You might also want to make sure you didn't pick up an STD. I pray that you can find the inner peace and assurance of forgiveness from our loving Lord, and also from your dear wife, and may this actually result in more closeness with her.