Is a divorce considered valid if it occurred under duress from the first wife and her family, with no intention of divorce, and this being the third such divorce?

What the first wife did—leaving the house and children and threatening to hit you—all of that is impermissible. However, it does not constitute duress for the husband to pronounce divorce. Therefore, your husband’s divorce has taken effect upon you. If this was the third divorce, then he has no way back to you unless you marry another man, a marriage of genuine desire and not for the purpose of making you lawful for your first husband, and then he divorces you and your waiting period from him ends.