Have you asked yourself what it is that you are fullfilling with the sister that you are not getting in the marriage?

Perhaps you are not having a physical affair but you are having an emotional one, which is depriving your wife of that part of yourself you are sharing with her sister.

Are there children involved? Either yours or the sisters? Maybe you should ask yourself what do you stand to lose and what do you stand to gain by choosing one sister over the other.

I sure hope you get this worked out so you can all be happy and so that nobody gets hurt.Good Luck! Faith