Caroline Rules

Secondly, you're assuming he's having an affair, correct? Before you make any decision to "out" your brother-in-law, you should consider the fact that you're about to drop a bombshell based on an assumption—no matter how strong it is. Think of the consequences. What if it's not true? What will this do to your relationship with your sister and her husband? You will immediately become the bad guy and potentially lose your sister in the process.

No one really knows what happens behind closed doors. Maybe your sister already has a feeling that something is going on and isn't prepared to deal with it, or maybe she has decided to deal with it her way, which is a happy front.

People have different ways of coping with different situations. I would suggest that you be a good friend to your sister and only be there to listen if the topic comes up. The bottom line is this: You say that your sister is happy? Well, there you go; that's your answer.