What should a woman do if she is unhappy being in an 'open marriage' where she can do as she pleases?

Well the institution of marriage is supposed to be giving 100% you love, consideration and devotion to one another. It does not sound as though this is what you have. Alot of people that are married have other arrangements that work for them. If you are not happy, why waste the little time on this godly earth you have and be in marriage that is unfulfilling as yours. Be honest with yourself and your husband and make a decision to either improve or remove. good luck