Is it permissible to marry a man who is already married and twenty years my senior, and who is unable to support his two wives?

Allah Almighty has made it obligatory for anyone who wishes to marry more than one wife to be just in spending, lodging, and housing. If one fears not being able to be just, then it is not permissible for him to do so, as Allah Almighty says: ﴿But if you fear that you will not be just, then [marry only] one.﴾ However, if the husband is a person of religion and good character, and the woman can endure a life of hardship, there is no objection to accepting marriage to him, for Allah has promised wealth to those who marry. If she cannot endure, there is no objection to refusing the marriage. Any unlawful relationship must be avoided.