Can I be fired without cause in Kansas City, Missouri?

I worked for an optometrist office that is a husband & wife sharing the practice. They are going through a divorce and tensions are high. I was hired by the husband to work part time on his days. I wasn't aware that he didn't tell her he hired me. The first day I met her she got in my face and said he had no right to hire me without her approval. I continued to work on his days as we agreed when he hired me. I went to work Monday and the wife blocked me from entering the building and said I was fired. I asked why I was being fired and she replied "I don't have to tell you anything". She was rude and hostile to me every time I saw her. My question is can she fire me when I didn't do anything wrong? My performance was praised by everyone but her. This was a personal issue between a husband & wife going through a divorce. He told me she fired me because she was mad at him. Is she in the wrong?