Is marrying a second wife secretly from the first wife, while ensuring the second wife's financial rights and with her family and some relatives knowing about the marriage, forbidden if the intention is to conceal the matter from the first wife for fear of the repercussions?

An 'urfi marriage (customary marriage) is valid if it fulfills the conditions and pillars of a marriage contract. However, it lacks documentation, which preserves rights and which may even become obligatory.

It is not permissible to write a will for the wife's inheritance now, because inheritance is tied to the time of death and the amount of the estate at that moment, and this does not solve the problem.

The woman's insistence on official registration of the marriage is her right and it is the correct approach to preserve rights. We advise you not to marry except through an official, documented marriage. You should carefully consider the consequences along with performing Istikhara (prayer for guidance).