My husband and I have reached the time of life when our friends’ children are getting married. So we’re going to a lot of weddings. As friends of the parents, we’re the least essential people in the room. But we’re thrilled to be invited. We’ve known some of these brides or grooms since they were adolescents, and a few since they were born.

Last weekend was the wedding of a close friend’s daughter. It was warm and intimate and wonderfully moving. The couple are obviously well-matched (to say nothing of head over heels in love). They were married by a family friend, and devised the ceremony themselves. They left God out of it, but did exchange the traditional commitment vows. All the parents seemed overjoyed. A wedding is a union not just of two people but of two clans. So the families, too, are joined now. The bride and groom have each acquired a second set of relatives, with a whole new web of joys and sorrows and surprises.

I didn’t always enjoy weddings as much as I do now. I never longed to be a bride. When I was in my 20s, I thought marriage was a dusty relic of the patriarchy. Weddings were a silly, conformist ritual full of fake piety, tasteless clothes and ostentatious spending. Who needed one? Not me. I longed for self-actualization and adventure – anything but the banality of coupledom and family life. I vaguely pitied the friends who chose to settle down early. They were cutting off so many of life’s possibilities.

I was wrong, of course. My friends should have pitied me, instead. They were getting along with the work of becoming mature, responsible adults, while I was in avoidance mode. They discovered then what I only discovered much later. Two are stronger than one, and the life you make together can be infinitely richer than the one you’ve lived alone. It’s their children – their remarkably accomplished, kind, sensible and optimistic children – who are getting married now.

In the past two generations, the cycle of marriage and maturation has changed radically, especially for the middle class. My mom got married at 18, when she and Dad were penniless college students. She popped out three babies by 26, and nobody thought twice about it. I never would have dreamed of doing that and, if I’d tried, my parents would have been rightly horrified. The new norm was that marriage had to wait until you’d finished your education. None of my friends got married until after university.

Today, finishing your education can take until you’re 25, or longer. Then you’re supposed to get a job, establish a career, pay off your student loans, build up some savings, maybe trek through Asia. These days, the average first-marriage age in Canada is 34 for men and just under 32 for women – the highest in the world, except for Spain. No wonder.

Marriage rates are in decline. But marriage as an institution is probably more important than ever. That’s because so many of our other institutions have faded away. Church, community, long-term jobs, and relatives within close reach can no longer be relied on to give continuity and structure to our lives. Without the purposefulness and shared goal-setting that tend to go hand in hand with marriage, many young adults today seem unmoored – adrift on a sea of casual relationships where nothing much is asked of them, and nothing much is offered.

Marriage also matters because it is indisputably the best arrangement for raising children. No government, no matter how well-heeled or well-intentioned, can offer an effective substitute for the devotion and parental investment of two nurturing adults. The young couples we know would make fantastic moms and dads. But if you’re a woman, it’s not always easy. My friend’s newly married 27-year-old daughter is a promising scientist with a newly minted PhD. Her younger sister is finishing law school. They’re at the ideal age to have kids – and also to be establishing themselves in highly competitive careers. Society needs to figure out better ways of helping them do both.

Next weekend, we’ll be at another wedding. The father of the bride is my husband’s oldest friend, and her mother – who died when she was just a girl – was his other oldest friend. The bride and groom, a strikingly good-looking pair, are one of those increasingly common biracial couples who are helping to turn Canada from a mosaic to a melting pot. We intend to drink a lot of toasts and dance the night away (okay, at least till 10). We’ll be among the least essential people in the room, but we’ll be witnesses, and that’s important.

Whenever I go to other people’s weddings, I remember mine. It was pretty special (at least to us). We devised the ceremony ourselves, and it was warm and intimate. We left God out of it, but did exchange the traditional commitment vows. Although we were well into middle age by then, all our parents were present, and seemed quite overjoyed (and also, on my side, mildly relieved). That day, I realized the marriage ceremony wasn’t only about us. It was as much about the friends and family who had come as witnesses, the second families we had gained, and the promises we made in public to each other and to all of them. I sometimes think of it as the day when I became a true adult. If only I’d known, I might’ve done it sooner.