Telling husband I slept with someone else?

I say forget the rules and ask yourself is it something that your husband would want to know. You know your husband better than anyone else does so only you can be the one to make that decision, but don't tell him for the sake of your conscious that will only help you not him, if he is the type that only wants to be told when he ask then only tell him if he asks and deal with any issues that you may have internal by yourself.