What is the ruling on a man marrying another woman without his wife's knowledge, given that he does not provide for their children?

Islam permits a man to marry more than one wife on condition of equitable treatment in maintenance and overnight stays. It is not a condition for the permissibility of polygyny that the first wife be informed. Similarly, a husband's failure to provide for his wife and children does not legally prevent him from marrying a second wife, unless this failure is due to his absolute inability to provide. The husband is obligated to provide for his wife and children equitably. The wife has the right to seek redress from her husband or to take her due from his property if he neglects to provide for her. The mother has the right to reclaim what she spent on her children if she did so with the intention of being reimbursed.