The Messenger (sallal-laahu-alayhi-wasallam) said: ”Having intercourse (with one’s wife) is a charity.” [1]

In this there is: Perfect enjoyment; Kindness towards a beloved wife; seeking reward, gaining reward equivalent to giving Sadaqah, exhilaration of the soul, expelling bad thoughts, lighten the soul, expel her strain [and yours]; lighten her body and balancing her temperament [and yours]. If this happens in a good way, with gentleness and a lot of passion, complete desire and seeking reward, there will not be any enjoyment equal to it. [2]

[1] [Reported by Muslim. Number 1674]

[2]An Excerpt from Rawdatul Muhibbeen Wa Nuzhatul Mush-taaqeen of Imaam Ibnul Qayyim. Page 187. Slightly paraphrased]