If a woman says to her husband, I am not your wife, it does not have any consequences, because the wife does not have the ability to divorce her husband by talaaq.
But if the man says to his wife, You are not my wife, then this is a metaphor for divorce, as was explained in the answer to question no. 100997.
The wife should avoid using such words, because her husband may get angry and say the same to her, or he may confirm her words and say, Yes you are not my wife, or words to that effect.
Marital problems should be dealt with in an atmosphere of love and understanding, paying attention to each partner’s rights.
May Allaah help us all to do that which He loves and which pleases Him.
And Allaah knows best.