I once wrote a magazine story about seven women—a grandmother, her five daughters, and her eldest granddaughter—who all wore the same wedding dress.

It had been taken in and let out, stained and cleaned and tenderly passed from woman to woman.

I learned a great deal from this family of smart, strong, stubborn women. I learned about the importance of tradition, the comfort and constraints of family, and our ability to love one another through the best and worst of life . . .

Mostly I learned that you put your broom where your mother put her broom.

Lambie, the eldest of the five sisters who all had animal nicknames (Bunny, Kitten, Robyn, and Dove), was speaking literally when she said this, but she might as well have been explaining the secret truth of all human behavior.

Lambie kept her broom in the pantry—“where it belongs." When she was newly married, a sister-in-law visited and was appalled to find that the broom wasn't next to the refrigerator—“where it belongs." Lambie mused,

“Whether they tell you or not, you know what people expect of marriage. They expect what they saw in their own household."

If your mom always put onions in her potato salad, chances are good that you put onions in yours. If your husband's father refused to leave for a road trip without checking the oil in the engine, you might as well pop the hood for your spouse before loading up the car.

It's almost unbelievable how much childhood imprints itself on each of us—whether we want it to or not.

Lambie and her sisters shared an industriousness that was a near-perfect reflection of what they saw from their mother, who'd raised seven children and helped her husband build a booming business from scratch.

Lambie deeply admired her mother's incredible work ethic and devotion to her children; she also resented the times when that devotion felt controlling. And once she had kids of her own, she couldn't help but want to hold sway over certain aspects of their lives, even when it caused friction between them.

I don't believe that we all turn into our parents—that seems too simplistic—but we certainly carry them with us...

and shouldn't be surprised if we occasionally channel them, in ways both good and bad.

And it seems like a pretty crucial premise to bear in mind when trying to understand—and coexist with—our partners. Is she tight with money? Instead of judging her for only leaving the waiter a 10 percent tip, it might be worth talking about her parents' attitudes toward finances.

Perhaps cash was sometimes scarce, so she'd been taught to save at every turn. You don't have to be okay with leaving bad tips, but at least you'll get where she's coming from.

The same applies to just about everything:

Cleanliness, exercise habits, comfort with physical affection, ideas about gender roles, and toilet paper preference. I, for example, buy whatever brand is on sale. If that happens to be “SandPaper Ultra Thin," so be it. My husband, Aaron, on the other hand, only likes the fluffy two-ply printed with a giggly cartoon mascot. Negotiations continue.

Psychologists have written about how important it is for couples to allow themselves to be influenced by each other, both in thought and behavior. That happens naturally whenever any two people spend a great deal of time together. You begin to use the same phrases and share similar worldviews.

But it will take years to match the influence held by one's family. This can be frustrating at the outset, but it's also an opportunity. You both will get to see another way of doing things and can then decide together what really works best for the two of you. Do you even like onions in your potato salad?

When I sat down with Lambie's sister Bunny, she told me that one of the secrets of her more than twenty-year marriage was that she and her husband consciously adopted the best of each of their upbringings for their life together.

They keep regular date nights, like his parents always did, but are tremendously focused on their children, just as her parents were. “It's the balance," she told me. “We really are a blend."

The trick is being open to the possibility that your partner's family traditions could have some advantages—at least occasionally.

I didn't ask Bunny where she kept her broom, but I'd bet it's in the pantry. Exactly where it belongs.

This excerpt was republished with permission from The Washington Post's Ellen McCarthy's new book, “The Real Thing: Lessons on love and life from a wedding reporter's notebook.