These couple are both my friends in college and it will really hurt me if I hear that bad things happened to their marriage. They have 2 kids and are still very young. I don't know what to advice her I am not an expert. What I know is that it's a human nature that we get attracted to other people anytime in our lives.
Cheaters always lie but they say woman's intuition is very strong however we cannot just confront our husband without any proof or validation. As a friend I told her to talk to her husband first about it. In my opinion it would be best to make a plan then choose the right time and place where you will have privacy so you can discuss things out.
I told her to be ready in case the husband admits. If he admit then this is really painful but she should decide if she can forgive and keep her husband. I guess if she can keep this just between the two of them the better, we don't know how the family would react especially the in-laws if they know it.