Spending For The Sake of Allah
Sa’d bin Abu Waqqas (radi Allahu anhu) reported in a Hadith included in the chapter of Intention, that Messenger of Allah (sal Allahu alaihi wa sallam) said, “Whatever you spend seeking thereby the Pleasure of Allah, will have its reward, even the morsel which you put in the mouth of your wife.”
[Sahih al-Bukhari and Muslim]
This Hadith also highlights the point that one should feed his family and children with the intention that it has been ordained by Allah. In that case, this natural instinct will become an act of worship for which he will be rewarded.
And Allah Knows Best!