What is the ruling regarding a person who claimed that the wife deliberately threw the wallet and robbed her husband, and that there was a woman who saw her throw it but he did not disclose her name, and what is the ruling on shunning this person?

You have thought well of your wife, for the default state of a Muslim is innocence, and it is not permissible to accuse a Muslim of evil without proof. As for one who falsely accuses her, it is permissible to boycott him for three days, and it is not permissible to extend this period except for a legitimate Sharia interest or when harm results from abandoning it.