It often feels romantic to believe that love blossoms between two very different people, but real-life relationships tend to tell a quieter, more familiar story. When researchers looked closely at couples across generations, they found that love usually grows between people who already have a lot in common.
A large study that analysed data spanning more than a century and involving millions of couples revealed a clear pattern. Partners often mirror each other in meaningful ways, from personality traits and education levels to habits and daily routines. Instead of being drawn to contrasts, most people end up choosing someone who feels familiar and aligned with their way of life.
This similarity shows up in shared values and lifestyles. Couples often agree on core beliefs, follow similar routines, and make comparable choices in everyday life. Whether it is political views, religious outlook, or habits like drinking and smoking, partners tend to be on the same page. Even physical traits such as body type or wearing glasses were found to be more alike than different.
The findings, published in Nature Human Behaviour, showed that a large majority of traits studied reflected strong similarities between partners. This challenges the popular idea that differences keep relationships exciting and instead highlights how comfort and understanding play a bigger role in long-term bonding.
Researchers suggest that this happens naturally because people with similar backgrounds often cross paths. Shared workplaces, neighbourhoods, social circles, and lifestyles increase the chances of meeting someone with comparable experiences and values. Connecting with someone who understands your daily life and worldview also makes emotional bonding easier and more natural.
That said, not everything lines up perfectly in relationships. Some traits, such as whether someone is a morning or night person, how outgoing they are, or small biological preferences, showed little overlap between partners. In a few cases, couples were even slightly different in these areas.
However, these small differences did not appear to affect the strength or success of relationships. The research suggests that personal quirks matter far less than shared goals, values, and ways of living. To deepen their understanding, the team also studied tens of thousands of couples from the UK Biobank, looking at everything from childhood experiences to hobbies like gaming.
Taken together, the findings paint a simple picture of love. Lasting relationships are less about sparks between opposites and more about finding comfort in someone who feels like home.
