Assalamulaikum, I have seen some Islamic Lectures that say that the man does not need to ask his first wife's permission, but also the first wife does not even need to know? Isn't this lying and deciet? How does such a thing become valid when it comes to a Man?

I understand the proof that he does not need the permission of a wife is the fact that the Quran makes it his right to marry more than one. But outside of the knowledge of the first wife?

Also does it count as unfair if the second wife knows of the first wife, and the first does not?

Bonus question: Can the man marry a second wife if he for decades did not fulfil the rights of a husband to the first wife and family. But now says he will give e.g £50 to his second wife and £50 to his first wife (a woman with also children who depend on her) ?

I think a lot of men abuse their right to marry more than one woman without honouring a woman's rights in Islam.

I have seen some Islamic lectures that say that the man does not need to ask his first wife's permission, but also the first wife does not even need to know? Isn't this lying and deceit? How does such a thing become valid when it comes to a man?

I understand the proof that he does not need the permission of a wife is the fact that the Qu'ran makes it his right to marry more than one. But is it valid outside of the knowledge of the first wife?

Also does it count as unfair if the second wife knows of the first wife, and the first does not?