Editor’s note: National Marriage Week is Feb. 7-14. World Marriage Day is Feb. 11.

On their wedding day, a bride and groom may have stars in their eyes, but they have rocks in their heads if they think their partner isn’t going to:

Drive them nuts. Sometimes.

Take them for granted. On occasion.

Do something that truly hurts them. Once in a while.

Husband does it to wife. Wife does it to husband.

There are moments — there can be periods — when those wedding-day stars are replaced with long-time-married sparks of anger. Even in a happy marriage. Even in a marriage filled with joy and grace because:

A marriage is made up of two imperfect people. (Yes, yes, your betrothed was perfect! But how he or she has changed! Or more correctly, how your perception has improved.) That’s why each person, at times, needs to seek forgiveness. Why each, at times, needs to offer it.

Enter mercy. Wedding homilists and marriage vows speak of love, honor and cherish, but mercy pops up again and again as the marriage progresses. And with mercy, that relationship does make progress. It broadens, deepens, intensifies.

If love is the engine that drives a marriage, mercy is the oil that keeps its many parts running smoothly.

What’s in this amazing fluid that goes such a long way on cutting down friction? The glossary of the Catechism of the Catholic Church puts it this way: Mercy is “the loving kindness, compassion, or forbearance shown to one who offends (e.g., the mercy of God to us sinners).”

No couple gets very far down the road of life together without one person offending the other. And the other person offending the one. Those unpleasant mileposts can demand loving kindness, compassion and forbearance (that is, patience and leniency).

Wonderful in theory. Pretty darned tough sometimes in the real world. And marriage is no honeymoon. It’s as real as real can get.

With all that in mind, here are a few points to consider:

To grow in love is to grow in mercy. God, all merciful, is love (1 John 4:8) and — thanks be to God! — a husband and wife were created in his image. But that growth in love and mercy isn’t like some beautiful piece of furniture delivered to your front door and placed in your home.

No, no, no. When it comes to virtues, God can be more like ... IKEA. Here’s a box crammed with parts, here are the instructions. Now, put it together! (Yes, his helpline is always open.)

How do you do that? The good news: He gives each of you a lot of opportunities to get better at loving and being merciful. The bad news: He gives each of you a lot of opportunities to get better at loving and being merciful. Practice won’t make you perfect, but it will make you much, much better.

Mercy talks, and mercy listens. It’s no secret that one of the cornerstones of a happy and healthy marriage is communication. But not all talking is created equal. Sometimes it’s so easy. (“That coat looks good on you.”) Other times, not so much. Other times, it’s saying things that are hard to say or hearing things that are hard to hear. (“Over the last couple of months your drinking has ...”)

It’s a wonderful, heady feeling to realize that someone who knows you better than anyone else on earth still loves you. Who, despite his or her awareness of your many faults and shortcomings, still truly loves you.

But that also means your spouse is the one who can tell you when you’ve started to go off course. Started to slip here or there. Started to become less like the person God created you to be.

Not that you or your loved one will ever reach that goal in this lifetime, but moving forward in that direction matters. To you. To him or her. To your marriage.

There’s a big — and important — difference between being merciful and being a doormat. A misguided sense of mercy can lead to a host of problems in a marriage. Mercy doesn’t overlook, ignore or simply dismiss an action or pattern that needs to be addressed.

At times it can rightfully and wisely call for professional help. A case of the sniffles? Maybe a nice bowl of chicken soup. A ruptured appendix? Much more sophisticated and professional care. A series of spats or a developing pattern of underappreciating each other? Perhaps a date night or setting up those evenings on a regular schedule. A larger and more complex problem — infidelity, addiction or abuse? Assistance from those educated and trained to help couples and individuals.

Mercy is always a choice — an action based on free will. Just as God will never force someone to be merciful, neither can one spouse force the other to act that way. Yes, over time, being merciful can seem like an automatic response, but that’s only because — as the years have passed — a person learns to offer mercy with grace and speed. It may appear effortless, but each time, whether for a small misdeed or large offense, mercy demands an action. Or, rather, four actions.

Being merciful is making the decision to be kind, compassionate, patient and lenient.

In “Misericordiae Vultus,” Pope Francis’ message announcing the Jubilee of Mercy, the Holy Father wrote:

“As we can see in sacred Scripture, mercy is a key word that indicates God’s action toward us. He does not limit himself merely to affirming his love, but makes it visible and tangible.

“Love, after all, can never be just an abstraction. By its very nature, it indicates something concrete: intentions, attitudes and behaviors that are shown in daily living. The mercy of God is his loving concern for each one of us. He feels responsible; that is, he desires our well-being and he wants to see us happy, full of joy and peaceful. This is the path which the merciful love of Christians must also travel. As the Father loves, so do his children. Just as he is merciful, so we are called to be merciful to each other.”

So you are called to be merciful to that wonderful, amazing, loving — and imperfect — person you married.

Bill Dodds writes from Washington.