Affairs are probably the most sensitive topic in relationships. Some people are ready to talk about their sex life rather than admit having an affair. You may not be cheating or cheated on, but what do you do when a friend comes confessing? As a friend, it is obvious that you have to be quiet about it, but beyond that, there is a certain attitude and series of thoughts that can make you a better helper.
Understand the situation fully: Affairs happen for a reason, but not always a strong one. Your friend may be having an affair because they are committed to a bad person which makes it easy for them to justify their actions. Other times, it happens just because they found someone else who is more compatible and / or interesting to them. Both cases do not give your friend the right to cheat, but bear in mind that they may not be aware of this. Talk to your friend to find out whether they know exactly how wrong they are or they believe they are excused due to certain circumstances. This will help pave the way for you to choose your words and get through to them easily.
Watch your tone: Do not let your belief that your friend is a criminal show up as you talk. Whatever the reason they chose to admit to you, you have to be considerate in your words and way of talking. Pointing fingers at your friend will take you now. You will not be able to listen to the true facts and feelings or give advice as long as you are being judgmental, even when you are right.
Consider the current relationship: Ask several questions about your friend's partner; has he / she changed? Are you two too busy to have a good time? Has the relationship become boring ?. Contrary to popular belief, it is rarely a problem with a partner that drives a person to cheating. We all have our problems and our fights, but normal couples fight the fight and move on instead of seeking perfection. In case of an affair, however, the cheating partner does not care either the other person is doing what they should or not. Even when fleeing a bad relationship, the magnetism that develops between your friend and the other person is often too strong that it blinds them from any improvement happening on part of their current partner. Remind your friend to take a closer look at what they have and focus on the positive side of their partner. Do not try to convince your friend to drop the affair for their partner's sake, unless you have something strong to discuss about. Trying to drive your friend into doing "the right thing" will only show that you do not understand how they feel.
Tell it like it is: Affairs do not have to be sexual. Long recurrent unexplained phone calls are an affair. Outings that nobody knows (or must ever know) about are an affair. Holding hands for an extra minute while crossing the street is an affair. If your friend is attracted to someone else, they will know when they are crossing the line and everything they do not dare confess to their partner or to other people is plain wrong. Sometimes, your friend may not be honest with themselves enough so you can not expect them to be honest with you. Nobody wants to be a cheater, so denial and simplification are definitely part of the equation to them. Clarify their actions to them and explain how far they have gone without notice. Talk as nicely as possible, but without ruining your point.
Confession is not your decision: If you believe the only way to move on is for your friend to come clean with their partner, keep it to yourself. It is not your place to decide that for them no matter what your morals are. You can tell your friend about honesty and try to talk them into confessing, but do not be too persistent. It will definitely annoy them and may shake the trust they have for you. It may convey the idea that if they do not tell their partner, you will, even if you have no intention of that.
Imagine the "what ifs": When people cheat, they do not even see half what the other person is really like. They just enjoy the good side they see at the time and live in dreams of perfection. As the time passes, the belief that this person is actually more "perfect" than the one they are with now may start to build up. This is only an illusion, so try to get your friend to see the real person as a whole. Ask your friend to visualize their life with the other person. Tell them to see the facts and imagine the person as he is, not just the side they want to see. It will help if you take the disadvantages you see in the person and anticipate the problems that could occur from them. Talk logically and wisely. Do not let yourself appear as someone who just wants to sabotage the other person. Base your ideas on trains really available in that person so your argument can be believable.
Talk about termination: Many people involve themselves in affairs with people what they have no intention of being committed to. They spend with them as much time as possible and have fun knowing that all this is going away some day and that they will always straighten up and get back to the person they are with. Tell your friend that it will make them the stronger and better person if they initiate terminating the affair. Also, things may be settled now, but if any crisis occurs with your friend's partner, they will be swamped. Your friend will be crushed between following an affair and having to be there for a sick partner or death of an in-law. Since those are just possibilities, try talking about facts relevant to their life. If your friend is taking their relationship with the committed person to the next level, having a new baby, moving to a new house, changing jobs or going through any new major change, help them see what a mess their life will be if something big is going on while they are emotionally distorted.
Resisting temptation is hard. Bear in mind that your friend trusts you dramatically to spill such a secret to you. Be there for them. Help them organize their life. Distract them while the hard times pass. Do anything you two agree to be helpful to them as they get through this rough experience, no matter what the outcome.