The ideal that marriage aims at is that of spiritual union through the physical. The human love that it incarnates is intended to serve as a stepping stone to diving or universal love.
Constancy has nothing virtuous in itself, independently of the pleasure it confers, and partakes of the temporizing spirit of vice in proportion as it endures tamely moral defects of magnitude in the object of its indiscreet choice.
Every relationship that does not raise us up pulls us down, and vice versa; this is why men usually sink down somewhat when they take wives while women are usually somewhat raised up. Overly spiritual men require marriage every bit as much as they resist it as bitter medicine.
Marriage was contrived for ordinary people, for people who are capable of neither great love nor great friendship, which is to say, for most people--but also for those exceptionally rare ones who are capable of love as well as of friendship.
Marriage is an institution that teaches a man regularity, frugality, temperance, forbearance and many other splendid virtues he would not need had he stayed single.