What should I do about my wife who refused to return to the marital home after demanding a separate residence which she knows I cannot afford, and should I be the one to initiate divorce, and what about the custody of my son after weaning?

If the husband stipulated to his wife that she reside in his parents' home due to his inability to provide a separate dwelling, then she does not have the right to demand a separate dwelling, unless she suffers actual harm from living with her husband's family. A wife leaving her husband's home without his permission is considered an act of defiance (nushooz) by which her maintenance (nafaqah) is forfeited (unless she is pregnant), while the child's maintenance remains obligatory upon the father. The husband is advised to communicate with his wife and remind her of her duties and his rights. If these attempts fail, wise individuals can intervene to reconcile them. If that does not work, the husband may refrain from divorcing her until she waives some or all of her rights. Divorce should be the last resort, especially when there are children, and it is preferable for the spouses to remain together, live amicably, and overlook some minor faults.