1. It is often asserted that the simpler the wedding ceremony, the more likely the marriage will be a success. But what's wrong with having a party? Even if it does cost £60,000 to entertain all your friends in a hotel over the space of three days.
2. One dodge is to marry in some exotic location abroad - that keeps down the cost because so many guests won't travel to Seville, Barbados or the Seychelles for the nuptials. A travel site specialising in destination weddings has seen a 14% increase in sales to faraway wedding locations over the space of a year.
3. But be sure that you get all the paperwork correct. There was a poignantly comical case of a group of Irish couples who married in Lourdes and only discovered several decades later that they were never legally married at all, as they had omitted a separate civil ceremony obligatory in France (Good rom-com movie material).
4. There's nothing wrong with a healthy row every now and again. Domestic violence is dreadful, but I'm not comfortable with the idea that a robust slagging-off constitutes emotional abuse. Moreover, when it comes to verbal invective, women are every bit the equal of men.
5. Togetherness is all very well, but it's refreshing to make space for separate hobbies just the same.
6. There was a British sociological study recently which claimed that bad girls make good wives. I can identify with that. Bad girls are less likely to imagine that the grass is greener on the other side of the fence - they've been there and they know it isn't.
7. Sex is essential to marriage. A 'marriage blanc', where consummation has not taken place, was always grounds for annulment. Yet there have been happy marriages which were sexless or became so. The writers Harold Nicolson and Vita Sackville-West had a blissfully contented marriage though he was a homosexual and she was (a highly active) lesbian. Nicolson's diaries are full of utter devotion to Vita and she relied on him totally.
8. Some old wives' advice about marriage: Kissin' don't last, cookin' do. Don't marry for money, but don't go courtin' where it ain't. My mother liked the Old Testament advice, "Never let the sun go down on your anger".
9. It is said that the best way to avoid a broken marriage is not to have divorced parents. An example from the royals: Diana was emotionally disturbed by her parents' bad marriage and distressing divorce. Kate Middleton is sensibly grounded because her middle-class parents seem to be in an intact and successful union.
10. Many cultures still practise arranged marriages, and it was not unusual in Ireland up to the 1940s (although, judging from literature, there could be a certain amount of stigma around a 'made match', even where the spouses were willing). Some Asians claim a skilled matchmaker can put couples together happily, with an emphasis on common interests, shared values and mutual respect.
11. But there's no accounting for the human heart. I knew a journalist who walked into the lift of a tall building, clapped eyes on a beautiful nurse therein and two weeks later they eloped - and lived happily ever after.
12. Can May-September marriages work? The conventional wisdom is that the dice are stacked against a big age gap, but look at Emmanuel and Brigitte Macron, with a 24-year difference, and the slightly, em, unusual background that she was his teacher when he was a teenage boy. They're still serenely together, but when he's 60, she'll be 84. Challenging.
13. The veteran agony aunt Irma Kurtz gives women this advice: "Never date a man you haven't smelled." I know a woman who couldn't decide between two swains, so chose the one whose smell attracted her. They're happy together.
14. International unions have become much more common with globalisation. But when Mary Banotti, as an MEP, found herself sorting out tug-of-love child problems occasioned by international marital separations, she came to the conclusion that there's a lot to be said for the boy (or girl) next door. National, ethnic or religious differences may increase friction. Just saying.
15. 'Marriage equality' has a nice ring to it, but I never did know of an equal marriage - it's a power struggle. But the power shifts in a successful union over the years - the weaker spouse can become stronger, and vice versa.
16. You just have to get along with your in-laws. Romeo and Juliet's marriage would have been wrecked if the Montagues and Capulets remained mutually hostile.
17. All systems have seen the purpose of wedlock as begetting children. Today, some couples simply don't want kids. But maybe they should ask, 'Do I want to be a grandparent?', rather than, 'Do I want to be a parent?'. The pioneering social reformer Beatrice Webb was certain she didn't want children during her hectic prime. Later on, she regretted this choice.
18. Byron said that "wedlock's the devil", but he didn't foresee the studies which tell us that you're likely to be healthier, saner, live longer, and be better-off financially if you are married.
19. A veteran husband's wise advice: "When you're wrong, admit it. When you're right, say nothing."
20. There are rules for maintaining marriage, but some partnerships which defy all the rules are wonderful nonetheless.