My 11-year-old son chastised me the other day. A car was driving very erratically in front of us on the road, and I blurted out, “What the ____ are they doing?”

“Mom,” he said gravely from the backseat, “We don’t say ‘heck.’”

Oh. Right. That is one of those so-so words that can lead to others. There are just some things we try not to say in our house—and some things we never say in our house. “Stupid” may not be a swear word, but we don’t say it. Not only it is hurtful to others, it is never going to increase goodness, kindness, patience, gentleness, or self-control in yourself. And letting that word become part of the vocabulary will inevitably lead to other thoughts, words, and actions—and none of them are exactly tasty fruits of the Spirit either.

So our list of so-called “four-letter words” includes several that aren’t swear words or even four letters, but which tend to lead to bad thoughts, words, or actions that will ultimately hurt each other or those around us.

It turns out that there is another word that our whole culture – and every married couple within it – needs to add to the list of four letter words that you should simply never say. I love this amazing article by a young woman whose parents removed the word “divorce” from their dictionary—quite literally. She captures so well the impact on a marriage and on children of knowing that a husband and wife will be together no matter what.

When you talk to as many people as I do throughout the course of the week—everyone from the person who comes up to me at the book table to the person I randomly stop on the street and ask research questions—you hear some common patterns in how they view life and relationships, and what makes for happy people rather than hurting ones. And one of the clearest threads I’ve seen both with adults and kids, is that a vital key to thriving in life and relationships is knowing a spouse will be there no matter what. (Or, if you’re a kid, that your parents will remain together no matter what.)

In your marriage, keeping your options open, even just a little bit, will only lead to pain. It creates a wall. Or it leads to the poisonous thought that maybe the grass might be greener over there because surely some other man wouldn’t do this thing that hurts me…

By contrast, when I was surveying happily married couples, including many couples who had gone from troubled to terrific, one of the most common denominators was that they (as one man put it) “locked themselves in the marriage and threw away the key.” With divorce removed as an option, with a commitment to never even say the D-word to each other, it created a sense of security in an insecure world, and eventually led to deep enjoyment and happiness in the marriage since the couple knew they had to work things through. There was no escape hatch “just in case.”

Now clearly, sometimes this isn’t always in our control; several of my closest friends are single moms today because their husbands abandoned them. But in a culture in which the D-word is thrown around as casually as many other four-letter words, I’m now firmly convinced that one of the greatest keys to delight instead of despair is—as far as it depends on us—to never use the word again.