An open marriage or an open relationship period in my opinion means that there is someone out there can do it better you can. It doesn't matter if you were the wife of King Tut, he is not allowed to be that disrespectful and ask his wife, the woman he vowed to spend the rest of his life with, to have an open marriage.
An open relationship can cause a lot of things that you can't control. For example, getting emotionally attached with many more but the main thing that it causes it a lot of pain and stress that you don't want or need for that matter. So, to answer your question, "If you were a basketball of football stars wife would you agree to an open marrige?" I'm going to have to disagree with that. Be selfish, because the rock is on your finger not theirs. You are his wife not those other women so why should you have to share?