In 1926, when Hope Mirrlees was asking her peers to gaze into the crystal ball of marriage, Somerset Maugham’s The Constant Wife was given its premiere on Broadway. The witty period piece has been revived again and again, and for good reason.

The entire play is an ironic exploration of the word “constant” — from the name of the heroine to the underlying theme of marriage as a constant in all our lives, but one in which the partners must continuously adapt to changing expectations and situations, including inconstancy. The closet homosexual Maugham, with a failed marriage to his name, expressed the awareness of women (who had, after all, had the right to vote for only eight years) that sexual independence comes only as a result of economic independence.

His resourceful heroine Constance Middleton says: “There is only one freedom that is really important and that is economic freedom” — and ultimately walks away from the marriage on her own terms. If Maugham was speaking from the Zeitgeist, his words still echo today through living room and law court alike.

The actress Fay Compton’s quaint assertion that “unadulterated love” would cement the marriages of the workers and Norma Talmadge’s naive trust that marriage would become “more beautiful” in the future contradict the “rough beast” of history, which always stirs, making change inevitable. So, after the Second World War, the influence of the Church diminishing, the number of married women in the workforce increasing, fertility declining sharply, marriages stretching into unutterable tedium as never before because of longer lives, and the demands of personal freedom and “happiness” becoming widespread . . . all these trends made the divorce figures creep up. Though there were still only 4,000 divorces a year, it was enough to sound the knell for “until death us do part” — and render risible Edward Oppenheim’s easy platitudes about the “sacredness” of marriage. Not when Maugham could put these words into an actress’s mouth: “I’m tired of being a modern wife — a prostitute who doesn’t deliver the goods.”

Still, Oppenheim’s implied view that stable marriage is the best place to raise children is one with which I find myself in sympathy — notwithstanding the devotion and success of so many single-parent families, divorced and unmarried. Asked to make my own prediction for 2026 or 2050 I worry whether (in pessimistic moments) I see the end of marriage — since I believe that the combination of companionship and children is still the best justification for tying the knot.

I see no virtue in politically correct neutrality: faced with two snapshots I know which one I think most likely to lead both to individual happiness and the public good. Here is the harassed young mother with two children by different fathers left alone to bring up those children on welfare, or cohabiting with yet another boyfriend who is statistically more likely to harm children who are not his own. Here is a nuclear family where the children have the security of knowing Dad and Mum care for them more than their own needs and weaknesses. My crystal ball grows murky if we persistently fail to see which is “better”.

The proportion of families headed by two parents has fallen below 75 per cent for the first time, and the statistics paint a grim picture of the effects on children.

I agree with Talmadge and Alec Waugh that the reasons people get married do not change very much (economic imperatives aside), for the summer wedding season is here, and couples are still touchingly compelled to share ceremonies, be seen as units and nest in rows. Why else would gay couples want to marry? And maybe there will be a backlash against what Bennett called the loosening of the “bonds of marriage”. Since independence of spirit, education and self-respect are surely now hardwired into the female gene — who knows? — perhaps girls in their twenties will feel chilled enough to choose fidelity to the conjugal vows, raising children as a vocation and working together as equals to turn marriage back into that “respected institution” which I still believe can be the bedrock. Or at least, a long-term source of contentment. Plus ça change . . .