I am sure it was a very huge shock .. I can see your pain and disappointment. You are sisters but its not uncommon to have drastically different thoughts views and " morals" regarding lifestyle.

There are so many types of relationships now .. If your sister and her husband both agreed that an open marriage is for them .. then you just have to allow them to conduct there lives as they wish. There marriage may last there lifetime who knows .

You are not your sister .. you have every chance in the world to find love and a wonderful marriage that will work for you.

Be kind to yourself