It is interesting to read the responses on this post. I know from experience that nothing anyone says to this couple is going to make them stop what they are doing and I"ll tell you why. When an affair is going on, its like living two lives. One normal life and one secret life. If people in your normal life tell you to change your secret life…the person pretty much forgets about it while engaged in the practices of the secret life. an affair is only fun while you’re getting away with it. Some people can marry the person they had an affair with and be fine. But it doesn’t normally work that way. My point is, just tell them how you feel talk to your priest, and pray. Stay out of it because they are not listening to you anyway. Don’t go behind their back and try to “punish” them by exposing their affair. They will be punished eventually. Their marriages will both break up and they will have to live with the mental anguish the rest of their lives. Unfortunately, so will the spouses. I know this all because i was involved with a married man from my workplace a few years ago. People tried to help me too and we even almost got caught a few times and we had to lie to get out of it. There was nothing anyone could do. To get out of it took quitting my job, making a conscious effort not to talk to him, blocking him from my email and messenger, and therapy. I still live with the residual effects of what I did and I will be eternally regretful. Don’t worry. This affair will all fall down upon them eventually. If you are a good friend you’ll be there with comfort and prayer. The friends that I still have after my affair are the best friends I’ll ever know. Be known as the friend who helped them up, not the one that brought them down. You can point out the sin to both of them. But let God do the punishing.