There’s one key aspect to a healthy marriage that can make your relationship last a lifetime

When sharing the secrets to a happy marriage, there’s one golden rule that comes to mind consistently for experts and longstanding couples alike: friendship. Because while love and lust are nice, of course, being real, honest, and true friends with your partner is the most important part of any relationship, particularly a marriage you’d like to see last.

While studying love and relationships during his professorship at Harvard, Dr. Arthur Brooks has shared that the most important kind of love is companionate love. According to the American Psychological Association, companionate love is “characterized by strong feelings of intimacy and affection for another person rather than strong emotional arousal in the other’s presence.” As the Encyclopedia of Social Psychology shares, companionate love is “also known as affectionate love, friendship-based love, or attachment.” While a guest on the podcast The Drive helmed by Peter Attia, MD, Brooks discussed the nature of companionate love and its importance to relationships, adding that “the goal of your marriage is not passion, it's friendship.” You really, actually, have to like each other.

  Dr. Arthur Brooks discusses the importance of companionate love with Dr. Peter Attia.   Dr. Peter Attia, MD www.youtube.com  

“You must be close friends, ideally, best friends, with your spouse,” Brooks continues. Because if you have kids who grow up and move away, what are you going to talk about when they’re gone? But if you have something to talk about–ideally some overlapping philosophies you enjoy discussing, Brooks says–and you enjoy each other’s company, your relationship is virtually unstoppable.

You may not always have passion; in fact, as Brooks says, it’s actually “healthy, normal and actually advisable” that it peters over time “because it's more sustainable over the long run.” But you don’t just have to take it from Brooks.

Below: Denzel Washington and Pauletta Washington have been married for 42 years.

The renowned psychologist Dr. John Gottman–founder of The Gottman Institute, whose goal is “to foster and sustain greater love and health in relationships”--believed this was the case as well. To continue creating friendship when you’ve been together for a long time, the Institute believes you need to keep listening, keep being interested, keep sharing your experiences, and keep being a good teammate.

Indeed, when answering the question, “What’s the secret to a happy marriage?” respondents in the Reddit thread r/AskOldPeople had the same thing to say. “Valuing our friendship together as much as our romantic interest in one another,” one person shared.

Below: Elton John and David Furnish have been together for 32 years.

“Marry someone you really, really like. Because if you’re doing life together, you’re going to go through a lot of shit. So much shit, y’all,” another shared. “You’ve got to have a partner who you genuinely love seeing walk into the room at least 90% of the time. It’s been 32 years and I still smile when my partner shows up.”

“I’d say my own marriage is happy because we like, love and respect each other,” one more poster added. “We also overlap a lot in values and interests although we each have our own hobbies. And we are not competitive with each other.”

Below: Tom Hanks and Rita Wilson have been married for 37 years.

  Tom Hanks shares what makes a happy marriage with 60 Minutes Australia.   60 Minutes Australia, www.youtube.com  

And while there will be work, and there will always be work, liking your partner in addition to loving them means there’s a much higher chance that you’ll want to show up to do that work, too. No relationship is easy, but if you and your partner are friends it can become so much easier.

Below: Michelle Obama and Barack Obama have been married for 33 years.

  Michelle Obama shares her marriage philosophy with NPR.   NPR, www.youtube.com