Is it valid to pray two rak'ahs of Sunnah every day with the intention of Salat al-Hajah before sleeping, in order to ask for a righteous, affectionate, and fertile wife?

The Ṣalāt al-Ḥājah (Prayer of Need) is recommended according to the majority of scholars. Their evidence is a Hadith from the Prophet, peace and blessings be upon him, who said: "Whoever has a need from Allah, or from one of the children of Adam, let him perform ablution well, then pray two rak'ahs. Then let him praise Allah, and send blessings upon the Prophet, peace and blessings be upon him, then let him say: 'There is no god but Allah, the Forbearing, the Generous. Glory be to Allah, the Lord of the Magnificent Throne. Praise be to Allah, the Lord of the Worlds. I ask You for that which will bring Your mercy, and Your determined forgiveness, and a share of every righteousness, and safety from every sin. Do not leave any sin for me unforgiven, nor any worry unrelieved, nor any need that is pleasing to You except that You fulfill it, O Most Merciful of the merciful.'" Ibn Majah added: "Then let him ask Allah for whatever he wishes of the affairs of this world and the Hereafter, for indeed, it is decreed." It is permissible to repeat it when there is a need, but it should not be committed to every night as a regular practice.