According to news reports, extramarital affairs are no longer the most common reason for divorce in the United Kingdom. Infidelity has been narrowly overtaken by couples “growing apart” or “falling out of love”. Apparently this statistical shift is due to the lingering economic uncertainty: couples who would normally have divorced over an extramarital affair chose instead to delay action in hopes of a better financial resolution.
The news that “falling out of love” is now the number one reason for divorce in the UK stirred a memory in me of the late Sir Harry Secombe, singing in the voice of his Goon Show alter-ego, accompanied by Peter Sellars on the timpani:

Falling in love with love is falling for make-believe
Falling in love with love is playing the fool…
I fell in love with love, with love everlasting
But love fell out with me! The idea that 27 per cent of marriages in the UK end because people simply “grow apart” or “fall out of love” makes me wonder what is really going on in these people’s lives. There’s no doubting that marriages – like any relationship – may turn sour; indeed, we should always bet on the likelihood that difficulties will emerge over time. We, more than most generations, have been given ample reason and opportunity to doubt the naïve ideal of marriage as one unbroken experience of “falling in love”. Yet, apparently, people still believe that the beginning and end of marriage should mirror the falling into and out of love.
Don’t go to a philosopher for relationship advice, because the first thing he might like to ask is: how do you define “falling in love”? Worse still, he might question the assumption that “falling in love” – however defined – is the underlying rationale for marriage.
As alarming as such questions might seem, their purpose is merely to clear the mind of preconceived ideas; ideas inherited from the culture without clear meaning. How many words do you “know” from their context, yet leave you grasping at straws when asked to define them? “Erudite“, perhaps? Finding the actual definition is like shining a light into the darkness.
“Love“, then, might not mean what you think it means. The trusty online etymology dictionary tells us that “love” originates in the Old English lufu meaning “love, affection, friendliness”, and that it is believed to derive ultimately from the Proto-Indo-European verb *leubh meaning “to care, desire, love”. “To fall in love” dates from the 1520s.
This seemingly slim record informs us that love has a good pedigree, but that its meaning has always been quite general. Love can pertain to friendship, though we don’t “fall in love” with our friends. Most significant is that love does not originate in the deeply specific context of affection between the sexes. If we try to trace the etymology further, we will find that “affection” originally means an inclination, and that “friend” comes from the present participle of a verb meaning “to favour”.
The point is that if we want to identify the first inklings of this thing called love, we can do so in the basic reality of our personal, idiosyncratic inclinations towards other people and other things. Like it or not, we aren’t naturally impartial beings. I like you more than I like him. I favour citrus over stone fruit. I’m more inclined to a 1796 Light Cavalry Sabre than a 16^th Century Rapier.
We respond differently to the differences around us, forming unequal affections and partial preferences. There’s nothing wrong with this, but nor is it the profound and mysterious basis for a romance novel. Set aside the vast cultural burden of love songs, love poems, romances and dramas, and replace it with the plain and prosaic truth that to love someone is, above all, to prefer them to others. Perhaps we can then define “falling in love” as the emergence of an inclination toward another person, a preference for that person above all others?
If we could content ourselves with this definition, it might be easier to foresee that a mere preference will not endure through a lifetime of marriage. After all, we could inject an element of doubt from the outset, and note that I can only prefer you above all others I’ve met thus far. Maybe I might prefer someone else even more? Surely we shouldn’t make such grand plans on the basis of an incomplete sample? 
Mere inclination is not enough, for our inclinations may change. Nor is it sufficient to bind ourselves with a great commitment, for the present age is happy to erase commitments and indulge our changing views. No, the key must surely be to take into account our weak and changeable nature from the outset. We need to assume from the very beginning that we will be assailed and harassed by the frailties of our own temperament. We need to plot our future course in full anticipation of fatigue, temptation, and the inevitable changes that arise in any relationship over time.
All the good advice I have ever been given about marriage looks to the future of the relationship, making decisions in the present for the sake of marital longevity. In this sense, though our choice of spouse may be guided by a love and affection that we have not chosen to feel, we must have near at hand the means and the willingness to make our marriage a self-renewing and enduring thing. The relevant choice is to approach marriage not merely as the affirmation of an experience, but with the goal of a self-renewing, living relationship that can endure despite shifts in fortune or in feeling.
If we can fall out of love, then we can fall back into it again. The real question is whether we will, from the outset, prepare ourselves to ride these peaks and troughs of feeling, or abandon ship at the first sign of rough weather. I won’t pretend to judge individuals who abandon their marriages for such reasons, but surely we can offer better advice to young people contemplating their futures together, in a culture and society so deeply wounded by error and experience? Zac Alstin works at the Southern Cross Bioethics Institute in Adelaide, South Australia.