Reference : Hisn al-Muslim 192

بِسْمِ الله 
اللّهُـمَّ جَنِّبْنا الشَّيْـطانَ، 
وَجَنِّبِ الشَّـيْطانَ ما رَزَقْـتَنا
Bismillāh. 
Allāhumma jannibnash-Shayṭān, 
wa jannibish-Shayṭāna mā razaqtanā.


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.

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

Chapter: Before sexual intercourse with the wife