You are married to Itachi because the organisation akatsuki forced you to marry him to prevent you from running away.You are a medical ninja who is a useful asset to the akatsuki. You hate Itachi and but you fear him that's why you obey him. Itachi on the other hand really loves you and treats you like his princess. Even though he is an introvert and has a troubled past. He always wants to protect you. He cares if you are a small child. One day you try to run away from him.