It’s common at award shows, as when Justin Timberlake said not long ago, “I want to thank my best friend, my favorite collaborator, my wife, Jessica.” It’s common on how-to sites, where authors write articles on “nurturing a friendship” with your spouse.

Like the living dead, another oxymoron, spouse-friends, are all around us these days. Maybe it’s the heightened attention on friendship in social media; maybe it’s the decline of actual friends in our lives; maybe it’s because we all have access to public declarations of once-private relationships. Whatever the reason, referring to your spouse as your bestie, your bud, or your #BFF has become rampant.

So rampant, in fact, there’s even a backlash. “Why Your Spouse Shouldn’t Be Your Best Friend” one marital advice blog declares.

So which is it? Is considering your spouse your closest friend a sign of hard-earned intimacy, attachment and trust, or is it a sign you’ve become so enmeshed in the day-to-day logistics of managing your lives that you’ve given up sexual attraction, passion and erotic play? Has marriage become little more than benefits with friendship?

There is some research into this question. John Helliwell is a professor at the Vancouver School of Economics and the editor of the World Happiness Report. As he researched social connections a few years ago, he found that everyone derives benefits from online friends and real-life friends, but the only friends that boost our life satisfaction are real friends.

“But while the effects of real friends on your well-being is important for everybody,” he said, “they are less so for married people than for singles. That’s how we got to the idea that marriage is a kind of ‘super-friendship.'”

Helliwell and a colleague discovered that a long-running study in Britain had data that may illuminate this question. From 1991 to 2009, the British Household Panel Survey asked 30,000 people to quantify their life satisfaction. In general, married people expressed higher satisfaction, he said, and were better able to manage the dip in well-being that most people experience in middle age, as they face work stress, caring for aging parents and other pressures.

But an entirely separate part of the study asked people to name their best friend. Those who listed their spouse were twice as likely to have higher life satisfaction. Slightly more men than women made that choice, he said, “which makes sense, because men tend to have fewer friends.”

Is feeling this way about your spouse necessary for a good marriage? I asked.

“Absolutely not,” Helliwell said. “The benefits of marriage are strong even for those who are littered with outside friends. It’s just bigger for those who consider their spouse their closest friend. It’s a bonus.”

Others are not so sure.

Amir Levine is a psychiatrist and neuroscientist at Columbia University, and the co-author of “Attached.” A student of social relations, Levine explained that everyone has what he calls a hierarchy of attachment, meaning if something bad happens to us, we have a ranking of the people we call. In our early decades, those on the highest rungs are usually our parents or other family members.

“The problem as you grow older is, how do you let somebody close who’s basically a total stranger?” he said. “Nature came up with a trick: It’s called attraction. Sexual attraction brings down all the barriers, lets you get close to a new person in a physical way that you don’t get close to your family.”

Over time, of course, this physical connection wanes. While many bemoan this loss of titillation, Levine celebrates it. “It’s smart,” he said. “If you’re going to be crazy about the other person all the time, how are you going to raise kids? How are you going to be able to work?”

Instead of complaining, we should view this new phase as an achievement: “OK, now I have this person I’m attached to. I have the feeling of security. That’s what allows me to be an individual again and self-actualize.”

Levine summarizes this feeling with the (somewhat awkward) acronym CARRP; your partner is consistent, available, responsive, reliable and predictable. But don’t we already have a word, “spouse,” that fits this description? I said. Why are we suddenly using the expression “best friend,” when that doesn’t seem to fit at all?

“Because not every spouse provides that,” he said, “and we’re indicating we don’t take it for granted. What we should probably be saying is ‘secure spouse.'”

There’s yet another problem with calling your husband or wife your best friend. The words mean totally different things.

Peter Pearson and Ellyn Bader are founders of the Couples Institute in Menlo Park, California, and the authors of “Tell Me No Lies.” They’ve also been married for more than 30 years. Pearson said there’s a critical difference between a best friend and a spouse. “One of the criteria for a best friend is you feel unconditionally accepted,” he said. “Do I care if my buddy Mark is messy in the kitchen, leaves his bathroom a shambles and doesn’t pay his income taxes?”

Bader said that when couples are just getting to know each other, they often say they’re companions, and she’s fine with that. When couples have been together 30, 40 or 50 years, they use similar language, and that can be the mark of a healthy relationship.

“It’s the in-between ones, when they use the language of friendship, my stomach turns,” Bader said. “It’s a red flag for a lot of conflict avoidance and intensity avoidance. It often means they’ve given up on the complexity of being with somebody. Instead of saying, ‘Oh, well, that’s who they are,’ it’s better if they try to work things out.”

Bader said that she wished popular magazines would challenge the notion that you shouldn’t get married to change someone. “I think that’s what marriage is about,” she said. “It’s where some of the juices come from, and it’s also how you get the best out of the person you marry.”