i am married, and recently had a child. however the wife is quite overworked with baby etc. hence our questions: can the man masturbate (without pornography or any other deviant material) simply because his wife is too tired with taking care of baby and work? and because he is scared that his needs and nufs (will) might falter and he may be tempted to do other wrong doing like zina or fornication?
No, masturbation is unlawful. If the postpartum period is over, you can have intercourse with your wife. If she is weak and unable to bear the intercourse, then husband can satisfy himself by touching any of her parts.
Allah (Subhana Wa Ta’ala) knows Best
Darul Uloom Deoband