We've all wondered if there's really a formula for the perfect relationship, right? Enter, the ‘triangular theory of love’ – a theory coined by psychologist Robert Sternberg, which suggests that there are three key elements that make up a successful romantic relationship.
Definitely not to be confused with the better-known ‘love triangle’, the triangular theory of love defines the three pillars that produce a well-rounded, loving partnership: intimacy, passion and commitment.
This explains A LOT.

American psychologist Robert Sternberg introduced the term in 1986, and deciphered a number of different types of love based within the triangle. He later developed his research into the ‘duplex of love’ when he combined his theory with another – the ‘theory of love as a story’.
But for now, let's stick to the triangle, which has caught the attention of a number of TikTokers. So, here's what you need to know about the triangular theory of love:
The triangular theory of love: the three elements
In order to form an ideal love, or a ‘consummate love’ as Sternberg puts it, a couple should have three things between them:
- Intimacy – rather than sexual intimacy, this refers to feelings of closeness and connection with the other person.
- Passion – this is about romance, physical attraction; the emotions that drive sex and desire.
- Commitment – this relates to a person's commitment to maintaining their love for another.
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Sternberg's theory also details the different types of love that can occur when the three triangular elements are out of balance. For example, ‘infatuated love’ happens when passion is there, but there's no intimacy or commitment.
‘Empty love’ is commitment without intimacy or passion, and ‘romantic love’ is passionate and intimate, but has no commitment. This is often used to describe an affair or a one-night-stand.
Other examples are ‘companionate love’, where the intimacy and commitment is there without the passion, and ‘fatuous love’ – passion and commitment, no intimacy.
How to find yours (and your partners).

How does the triangular theory of love apply to long-term relationships?
GLAMOUR spoke to relationship psychologist Professor Janet Reibstein, Professor Emerita at the University of Exeter and author of Good Relations: Cracking The Code Of How To Get On Better, about how the triangular theory of love might translate into our own relationships.
Of the basic principals of the triangle, she agrees that they make a great basis for any lasting romantic relationship. “These three markers absolutely are important for a successful relationship,” she says. “You can start out feeling that you're in love because you have the passion, but that does not mean that it goes into love – you have to go into these steps of discovering whether you have mutual understandings (which Sternberg would call 'intimacy'), and then you get to whether or not you both feel that this is the choice you want to make to be together, and that's the commitment. That is the genesis of an enduring partnership, that you have to work at over a lifetime.”
However, she does caution that while the theory makes for a good guide, it's important to remember that all partnerships have ebbs and flows. “If the triangle is the base, this consummate love, this big ideal that you should have all three things – yes, that's how it starts out, but the lived experience is that you go back and forth between these things,” she says.
“If you're in an enduring, lived relationship, you go through periods where one becomes more dominant over another, and you go in and out of those. The problem is that people think it should be constant and steady all along, and they give up, they start to conclude that things aren't working.”
Over half of UK couples admit they feel friction in their relationships because of the cost of living crisis.

What if something is missing in my relationship?
Professor Reibstein stresses that our lived experiences don't always match exactly to a specific formula – and labelling our relationships as ‘fatuous’ or ‘companionate’ isn't always helpful.
“When you label it that way, you go 'oh it must be that, this isn't real love',” she says. “In fact, we may have feelings of relationships becoming sterile, for example, or that we don't feel connected – maybe that's the 'fatuous love'. But in couple's therapy, we work towards what's been there before. How you interact together is how these things wither, or come alive again. Calling it 'fatuous love' kind of deadens it. People say 'love dies', but it doesn't really, you create it or you make it wither. It's how you are together that makes it love, or makes it not love.”
“I think you need to monitor, and you want to get those components back into some kind of balance – if they start to wither, you want to get them alive again,” she adds. “But monitoring is the point, rather than feeling like they have to be the same level all the time.”


