It’s the eternal question: What makes a romance work?

Let’s face it, most of the time, it doesn’t. According to one study, about two-thirds of couples break up within the first year.

But when it clicks, it really clicks: The same study found that if couples make it five years, the odds they’ll break up dips to 20%, and it goes down from there.

We decided to ask those who knew best, heading out on the streets of Manhattan to query long-time couples about the secrets to a lasting relationship, keeping romance alive, and how they knew that they’d found “the one.”