The other night while I was out food shopping I saw one of my friends cheating on her husband. The supermarket has a Starbucks in it and as I was walking towards it to get myself a coffee I saw her standing online, she was wearing a very skimpy outfit which was kind of shocking to see considering she usually dresses very conservative. I was about to call out to her but when she turned around she had two cups in her hand and went and sat down with some guy. I thought maybe it was just a friend but the way she was dressed really seemed strange. I decided to stay out of her line of sight and watch them for a minute. Sure enough after she handed him his coffee he reached over and began to kiss her. I got all freaked out and got as far away from them as I could. After I got in my car I decided to wait and see if I could see them leaving together, I was thinking maybe it wasn't her. But then I noticed her car, so I parked a few cars away and waited. About ten minutes later they walked out together holding hands, she got in her car and he got into his car and they drove off. I followed them. They went to a motel. I know I am wrong for not just minding my business, but I couldn't help myself. I haven't told anybody, not even FI. I feel bad for her husband he is such a sweet guy and I know it doesn't mean much but he is way better looking than the dude in the coffee shop. I don't think I am going to say anything to anyone, is that wrong of me. They are more of a second tier set of friends and we do not hang out with them very often and I feel like it is not my place to get involved. Am I wrong for feeling this way?