Editor's note: This post by Justin Davis originally appeared on RefineUs.org. It has been posted here with permission.

A few months ago, I was running late one morning (not unusual) and needed to swap cars with my wife Trish before I could head to my meeting. Trish called me and said, “Your car needed gas, so I am filling it up for you. Why don’t you meet me at Kroger, and you can leave from there. It will save you from having to stop and get gas.”

You are thinking what I was thinking: “My wife is amazing.”

So I left and went to Kroger. I drove around and around and couldn’t find Trish. About half way through my third lap around the parking lot, Trish called me.

“Where are you?”

“I’m at Kroger, where are you?”

“Which Kroger? I’m at the one on Highway 100.”

“Well, I’m at the one on Highway 70. I’ll stay here and you can meet me here,” I said and hung up the phone.

As I sat there, I started to get more and more angry. I was going to be really late now. This was all her fault. If she would have gone to the right Kroger in the first place, I wouldn’t be late to my meeting.

In that moment, I felt God speak to my heart: “Are you really going to be angry with your wife when she went out of her way to serve you? Where is the grace in that?”

By the time Trish got there, my anger had left, and I felt appreciative for all she had done to try to get me to my meeting on time. She didn’t cause me to run late; we just both accidentally went to the wrong location.

There was no malice. There was no ill-intent.

As we’ve interacted with thousands of couples over the past four years, we've seen one missing ingredient that causes a marriage to struggle: grace.

When a marriage is missing grace, the entire disposition of the relationship changes.

Little things cause big fights.

Motives are constantly questioned.

Tempers are short and often lost.

Assumptions are always made.

Conclusions are frequently jumped to.

Husbands and wives consistently lead with anger.

The past is always brought up.

The score is always kept.

When grace is missing from a marriage, three words dominate that relationship: You. Owe. Me.

A lack of grace will cause a husband to be furious with his wife for going to a different gas station than he went to. A lack of grace will cause a wife to notice all that her husband does wrong and not see all he does right.

It is easy to give grace to others and refuse to give it to your spouse. You can’t show grace to someone you are trying to make pay.

If you want to see change and improvement in your marriage, take a few minutes this week to think about how messed up and imperfect you are — and how God loves you anyway. That is grace.

So many couples try to correct their behavior or change their communication patterns, but without grace those changes are temporary and exhausting. Grace is the starting point from which all change is made.

When you connect your heart to the grace of God, it becomes much easier to dispense that grace to the person you love the most.

Justin and Trisha Davis are the founders of RefineUs Ministries, using their story of failure, loss and transformation to guide individuals, couples, churches, pastors, pastors' wives and church planters toward a healthy marriage and family. They live in Nashville, Tenn., with their three sons.