Marital relations are a private affair and there is a greater spiritual connection that is linked with marital intimacy in Islam. It is considered to strengthen the bond of the married couple and carry forward a progeny of their own. Dua before sexual intercourse is recited to seek refuge in Allah (سُبْحَانَهُ وَتَعَالَى) from satan and his evil whisperings. Marital relations are only the business of spouses of each other and are a matter that should not be known to anyone.
While a lot of people would shy away from talking or asking about any supplication or dua before this activity, Islam teaches married couples to see in prayer pious offspring and for them to be protected from any evil force. Narrated by Ibn Abbas and reported in Hisn al-Muslim 192, Prophet Muhammad said that anyone who intends to have sexual intercourse with their wife and recites this supplication and asks for a child, Satan will never harm that child.
Home & Family Duas
Bismillaah. Allaahumma jannibnash-Shaytaana, wa jannibish-Shaytaana maa razaqtanaa.
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.
The etiquette of making dua before sexual intercourse is based on the fact that both spouses should recite this dua before getting intimate with each other. The dua should be made only for Allah's sake without discussing an extremely private matter with others.
The benefits include protection from any evil forces and energy. While this act cements the relationship of husband and wife, making dua protects their offspring that is born as a result of their sexual intimacy. It reminds one that there is satan and Jinn and reassures one that Allah (سُبْحَانَهُ وَتَعَالَى) is the protector against all evil and negative forces.