The longest-married couple in the world celebrated their 86th wedding anniversary in 2010. Married in 1924, Herbert and Zelmyra Fisher were together for almost nine decades before passing away in 2011 and 2013, respectively. Herbert died a few months before their 87th anniversary at the age of 105.

Most of us can’t fathom living that long, much less spending a lifetime with someone — anyone. One can imagine that by the time Herbert Fisher passed away, they could barely remember what it was like not to have each other.

So, what was their big secret? It turned out, the Fishers didn’t have one. As they said, they were best friends before they fell in love. Then they spent more than eight decades taking care of and doing what was best for one another.

It was a challenging road, but they had a lifetime of happiness together. And many of us envy that.

While most of us won’t be lucky enough to experience 87 years of marriage, there’s a good chance we’ll be with our partner for many years. How do you achieve a happy marriage for decades? Here’s the secret from 70 couples who’ve been married for more than 50 years.