“He’s not the man I married,” one friend told me.

“She didn’t change, and I did,” said another.

And then there was the no-fault version: “We grew apart.”

Emotional and physical abuse are clear-cut grounds for divorce, but they aren’t the most common causes of failing marriages, at least the ones I hear about. What’s the more typical villain? Change.

Feeling oppressed by change or lack of change; it’s a tale as old as time. Yet at some point in any long-term relationship, each partner is likely to evolve from the person we fell in love with into someone new — and not always into someone cuter or smarter or more fun. Each goes from rock climber to couch potato, from rebel to middle manager, and from sex crazed to sleep obsessed.

Sometimes people feel betrayed by this change. They fell in love with one person, and when that person doesn’t seem familiar anymore, they decide he or she violated the marriage contract. I have begun to wonder if perhaps the problem isn’t change itself but our susceptibility to what has been called the “end of history” illusion.

“Human beings are works in progress that mistakenly think they’re finished,” the Harvard professor Daniel Gilbert said in a 2014 TED talk called “The Psychology of Your Future Self.” He described research that he and his colleagues had done in 2013: Study subjects (ranging from 18 to 68 years old) reported changing much more over a decade than they expected to.

In 2015, I published a book about where I grew up, St. Marks Place in the East Village of Manhattan. In doing research, I listened to one person after another claim that the street was a shadow of its former self, that all the good businesses had closed and all the good people had left. This sentiment held true even though people disagreed about which were the good businesses and who were the good people.

Nostalgia, which fuels our resentment toward change, is a natural human impulse. And yet being forever content with a spouse, or a street, requires finding ways to be happy with different versions of that person or neighborhood.

Because I like to fix broken things quickly and shoddily (my husband, Neal, calls my renovation aesthetic “Little Rascals Clubhouse”), I frequently receive the advice: “Don’t just do something, stand there.”

Such underreacting may also be the best stance when confronted by too much or too little change. Whether or not we want people to stay the same, time will bring change in abundance.

A year and a half ago, Neal and I bought a place in the country. We hadn’t been in the market for a house, but our city apartment is only 500 square feet, and we kept admiring this lovely blue house we drove by every time we visited my parents. It turned out to be shockingly affordable.

So now we own a house. We bought furniture, framed pictures and put up a badminton net. We marveled at the change that had come over us. Who were these backyard-grilling, property-tax-paying, shuttlecock-batting people we had become?

When we met in our 20s, Neal wasn’t a man who would delight in lawn care, and I wasn’t a woman who would find such a man appealing. And yet here we were, avidly refilling our bird feeder and remarking on all the cardinals.

Neal, who hadn’t hammered a nail in all the years I’d known him, now had opinions on bookshelves and curtains, and loved going to the hardware store. He whistled while he mowed. He was like an alien. But in this new situation, I was an alien, too — one who knew when to plant bulbs and how to use a Crock-Pot, and who, newly armed with CPR and first aid certification, volunteered at a local camp. Our alien selves were remarkably compatible.

Several long-married people I know have said this exact line: “I’ve had at least three marriages. They’ve just all been with the same person.” I’d say Neal and I have had at least three marriages: Our partying 20s, child-centric 30s and home-owning 40s.

Then there’s my abbreviated first marriage. Nick and I met in college and dated for a few months before dropping out and driving cross-country. Over the next few years, we worked a series of low-wage jobs. On the rare occasions when we discussed our future, he said he wasn’t ready to settle down because one day, he claimed, he would probably need to “sow” his “wild oats” — a saying I found tacky and a concept I found ridiculous.

When I told Neal about this years later, he said, “Maybe you found it ridiculous because you’d already done it.”

It’s true that from ages 16 to 19 I had a lot of boyfriends. But with Nick, I became happily domestic. We adopted cats. I had changed in such a way that I had no problem being with just one person. I was done changing and thought he should be, too. Certainly, I thought he should not change into a man who sows oats.

When we got married at the courthouse so he could get his green card (he was Canadian), I didn’t feel different the next day. We still fell asleep to “Politically Incorrect” with our cats at our feet as we always had.

We told anyone who asked that the marriage was no big deal, just a formality so the government wouldn’t break us up. But when pressed, it was hard to say what differentiated us from the truly married beyond the absence of a party.

When I grew depressed a few months later, I decided that he and our pseudo-marriage were part of the problem. After three years of feeling like the more committed person, I was done and asked him to move out. When he left, I felt sad but also thrilled by the prospect of dating again. A couple of years later, I met Neal.

Recently, I asked Nick if we could talk. We hadn’t spoken in a decade. He lives in London now, so we Skyped. I saw that he looked almost exactly as he had at 22, though he’d grown a long beard. We had a pleasant conversation. Finally, I asked him if he thought our marriage counted.

“Yeah,” he said. “I think it counts.”

We were married, just not very well. The marriage didn’t mean much to us, and so when things got rough, we broke up. I had been too immature to know what I was getting into. I thought passion was the most important thing. When my romantic feelings left, I followed them out the door. It was just like any breakup, but with extra paperwork.

Nick now works at a European arts venue. He’s unmarried. I wouldn’t have predicted his life or his facial hair. I don’t regret our split, but if we had stayed married, I think I would have liked this version of him.

My hair is long and blond now. When Neal and I met, it was dyed black and cut to my chin. When I took to bleaching it myself, it was often orange, because I didn’t know what I was doing.

Now I weigh about 160 pounds. When I left the hospital after being treated for a burst appendix, I weighed 140. When I was nine months pregnant and starving every second, I weighed 210. I have been everything from size 4 to 14. I have been the life of the party and a drag. I have been broke and loaded, clinically depressed and radiantly happy. Spread out over the years, I’m a harem.

How can we accept that when it comes to our bodies (and everything else, for that matter), the only inevitability is change? And what is the key to caring less about change as a marriage evolves — things like how much sex we’re having and whether or not it’s the best sex possible?

One day in the country, Neal and I heard a chipmunk in distress. It had gotten inside the house and was hiding under the couch. Every few minutes, the creature let out a high-pitched squeak. I tried to sweep it out the door to safety with a broom, but it kept running back at my feet.

“Wow, you’re dumb,” I said to it.

“I got this,” Neal said, mysteriously carrying a plastic cereal bowl. “Shoo it out from under there.”

“That was really impressive,” I said.

“I know,” he said.

To feel awed by a man I thought I knew completely: It’s a shock when that happens after so many years. And a boon. That one fling of a bowl probably bought us another five years of marriage.