And she asked her husband, if your first wife finds out, he said: she won't find out. If your first wife finds out, will you divorce me? He said: no.
And the marriage continued, after four months she found out.
His middle wife, so he decided to divorce the second.
So she asks, what is the ruling? It is not allowed. Even if he did not promise you, it is not allowed for him to divorce without a reason, because it causes harm.
This is a harmful divorce, this is a harmful divorce, it is not allowed for him to harm her, as a person.
He sees in himself, as the Blessed and Exalted said: But if you fear that you will not be just.
Then one, if he sees in himself that he cannot, he says she does not know, why? She will know sooner or later.
Either you marry while you are able to bear this responsibility, or you do not marry.
But to marry and then leave this woman hanging, harm her, and then divorce her after that—Allah protect us—this is absolutely not allowed.