Before sexual intercourse with the wife1 du'a

With the Name of Allah. O Allah, keep the Devil away from us, and keep the Devil away from that whic...

Reference:Al-Bukhari 6/141, Muslim 2/1028.Hisnul Muslim 192

بِسْمِ الله اللّهُـمَّ جَنِّبْنا الشَّيْـطانَ وَجَنِّبِ الشَّـيْطانَ ما رَزَقْـتَنا

Transliteration

Bismillāh. Allāhumma jannibnash-Shayṭān. wa jannibish-Shayṭāna mā razaqtanā.

Translation

With the Name of Allah. O Allah, keep the Devil away from us, and keep the Devil away from that which You provide for us.