As we move into National Kindness Day on November 13th, what comes to mind is my work with couples and how kindness is at the core of successful relationships. Turns out, it isn’t how much passion you have, how much money you have, or how many kids you rear–it all comes down to kindness.

In my sessions, I call this kindness “grace,” and what I mean by that is really “emotional latitude.” For example, your husband comes in late from work (again), and you have a couple of kindness-options. You can tell the nefarious story, “Home late again! I guess he really IS an inconsiderate fool!” OR, you can take the option full of grace, “Home late again! Poor guy, I bet his mean boss made him stay late again!”

What we know is that the more couples are apt to use the second story, the more kindness that perpetuates through the relationship. After all, if you show your partner grace, maybe your partner will return the favor.

There are even some stats behind this theory–imagine you come home with a piece of great news. Let’s say you just got a big promotion at work. What happens when you share that news? Does your partner jump for joy with you and share in your excitement (kind approach)? Or does your partner barely look up from the laptop (unkind approach)?

Couples who use the “kind” approach at least 87 percent of the time or more end up staying together and report happiness six years after their relationship is studied. Those who only use the “kind” approach 23 percent of the time often don’t even make it to six years.

When a couple comes in to talk about where things are going wrong, oftentimes it comes back to this–are you being kind to your partner? Or are you messaging that you don’t really care?

Turns out, the answer means way more than you think!