The opposite sex likes your wife, and chatting with her can only prove that the man intends to have an affair with your wife, but it can't prove that your wife has an affair with her, let alone that your wife likes him. Of course, you can't be sure that your wife is having an affair. As for why your wife cheated, it has something to do with your usual contacts. The lack of communication between two people leads to mutual distrust. If you don't trust her, there will be all kinds of suspicions that will make her unhappy. If she doesn't trust you, she will talk to someone else. The most important thing for you two is to understand and trust each other, so that you can share your inner thoughts with each other instead of hiding them. This will lead to the breakdown of marriage.