Preferring a pious spouse means happiness and also a decision that will result in eternal salvation because spouses who support themselves spiritually protect one another from harams and become a encouraging factor for gaining Allah’s consent.
About this subject, Badiuzzaman Said Nursi says;
According to the Shari’a, the husband should be a good match for the wife. That is, they should be suitable to one another. The most important aspect of this being suitable is from the point of view of religion. (The Flashes)
According to Nursi, spouses should be a good match in terms of piety, high ethics and fearing from Allah (SWT). A man who takes the religiousness of his righteous wife as a model and loves her for her morals and piety so as not to lose his companion of eternity is regarded to have gained worldly and other worldly painfree happiness. A woman is regarded to have gained eternal happiness who sees the religiousness of her husband, adheres to religion herself so as not to lose her everlasting friend and companion.
Otherwise, a man who commits evil deeds that will cause him to lose his righteous wife eternally will ruin himself. And a woman who does not take her husband who tries to live with taqwa as a model that will cause her to lose her husband will ruin herself. If a woman and man copy each other’s debauchery, sins and bad deeds and throw each other into fire they will ruin their love and happiness. (see ibid)
Said Nursi states that
A man who bases his love on the beauty of the good manners and ethics of the woman and the fact that she is the source of compassion and a gift from Allah rather than her material and physical beauty will receive love and respect from his wife in the same way; he adds that the mutual love and respect will increase as both spouses get old and ugly; thus, the worldly life will turn to happiness and that the love based on physical beauty will soon end and it will be replaced by conflict. (Sözler: Words)
As Badiuzzaman Said Nursi puts it, to love one’s spouse based on her fine compassion, beautiful characters, good manners and high ethics and thus to protect oneself from committing sins will enable him to receive from the All Compassionate his spouse in a more beautiful attractive and charming physical and spiritual beauty than the houris of Paradise in the hereafter as an eternal spouse, fine friend and a loyal lover.(see ibid)