Don't try to find out if he has a mistress.

- Dear, do you have a mistress? - Oh sure. I'll show you the pictures. Do you really expect such a development of the dialogue? Of course, perspiration will come out on his forehead. But this will not be proof that he eats dumplings on the side. Maybe he's just about to. Or maybe he's not hungry at all. Or maybe he has stomach problems and is worried? In response to your aggression, the husband will clean up the browser history, export bookmarks with porn, change the password on the phone and walk around with the face of a holy martyr sentenced to be burned. But this does not mean that he had a mistress. Men in general tend to be afraid that you will find out "something is wrong" long before the problem arises. Even more, they tend to worry that you are restricting their little freedoms, like the freedom to believe that they have freedom.