For most of recorded history, people married for logical sorts of reasons: because her parcel of land adjoined yours, his family had a flourishing business, her father was the magistrate in town, there was a castle to keep up, or both sets of parents subscribed to the same interpretation of a holy text. And from such reasonable marriages, there flowed loneliness, infidelity, abuse, hardness of heart and screams heard through the nursery doors. The marriage of reason was not, in hindsight, reasonable at all; it was often expedient, narrow-minded, snobbish and exploitative. That is why what has replaced it — the marriage of feeling — has largely been spared the need to account for itself.

What matters in the marriage of feeling is that two people are drawn to each other by an overwhelming instinct and know in their hearts that it is right. Indeed, the more imprudent a marriage appears (perhaps it’s been only six months since they met; one of them has no job or both are barely out of their teens), the safer it can feel. Recklessness is taken as a counterweight to all the errors of reason, that catalyst of misery, that accountant’s demand. The prestige of instinct is the traumatized reaction against too many centuries of unreasonable reason.

But though we believe ourselves to be seeking happiness in marriage, it isn’t that simple. What we really seek is familiarity — which may well complicate any plans we might have had for happiness. We are looking to recreate, within our adult relationships, the feelings we knew so well in childhood. The love most of us will have tasted early on was often confused with other, more destructive dynamics: feelings of wanting to help an adult who was out of control, of being deprived of a parent’s warmth or scared of his anger, of not feeling secure enough to communicate our wishes. How logical, then, that we should as grown-ups find ourselves rejecting certain candidates for marriage not because they are wrong but because they are too right — too balanced, mature, understanding and reliable — given that in our hearts, such rightness feels foreign. We marry the wrong people because we don’t associate being loved with feeling happy.

We make mistakes, too, because we are so lonely. No one can be in an optimal frame of mind to choose a partner when remaining single feels unbearable. We have to be wholly at peace with the prospect of many years of solitude in order to be appropriately picky; otherwise, we risk loving no longer being single rather more than we love the partner who spared us that fate.

Finally, we marry to make a nice feeling permanent. We imagine that marriage will help us to bottle the joy we felt when the thought of proposing first came to us: Perhaps we were in Venice, on the lagoon, in a motorboat, with the evening sun throwing glitter across the sea, chatting about aspects of our souls no one ever seemed to have grasped before, with the prospect of dinner in a risotto place a little later. We married to make such sensations permanent but failed to see that there was no solid connection between these feelings and the institution of marriage.