“Love is a verb.”

This is a beautiful description of how relationships work that accords with how so many big changes in life really happen. Success doesn’t happen overnight, neither does physical fitness, and neither does relationship breakdown. Nearly all big goals come from weathering small setbacks and making steady forward progress over days and months and years. And then there’s often one big breakthrough. Outsiders only see the dramatic final stages of the process, but the roots are generally deep.

The best part of Sexton’s interview isn’t his explanation of how marriages decay, however. It’s the solution he offers couples. It’s only four words long, so no one has any excuse for forgetting it: “Love is a verb.”

“I’m a romantic, but I don’t believe in fairy tales. I think that we sell people a bill of goods about what love is supposed to look like. Love is a verb,” he insists. “Falling out of love is very slow. It’s a very gradual process. You put on weight slowly. … You don’t just wake up one day and you’ve gained 20 pounds. You very slowly gain weight, but sure enough, it happens. It’s the same thing with love.”

And not falling out of love, like not gaining weight, isn’t about dramatic gestures or heroic acts. It’s about a relentless daily commitment to small actions. It’s about doing things — not clamming up to avoid the fight, not complaining about how the towels are folded, reaching out a hand in a tense conversation. In other words, it’s a verb.

“If you want to keep your love alive, you have to be attentive to all the little things that go wrong along the way, and constantly course-correct. If you can do that, you’ll never set foot in my office,” Sexton concludes.