The cliche that “opposites attract” is so rampant in relationship discourse that it is often just passed by. However, the idea that a seemingly mismatched pair of partners are actually perfect for one another is not only true anecdotally, but there is substantial psychological research to support it. While everyone’s definition of “Happily Ever After” is different, understanding that yours may be found in someone who is quite different from yourself is an important step in the dating game. [Related: What You Ought to Know Before Getting Into a Relationship]

What the Experts Say

One need look no further than Hollywood power couples (both the successful and not-so-successful ones) to understand how being too similar and very different can impact the long-term health of a relationship. Examples of “perfect” couples who fall apart for seemingly no reason, such as Brad Pitt and Jennifer Aniston and Elizabeth Taylor and Richard Burton, point to the problem of being with someone so much like yourself: it gets boring.

On the other hand, the dynamics of difference, a la Brad Pitt and Angelina Jolie and Michael Douglas and Catherine Zeta-Jones, actually fuels relationship longevity. When partners present each other with a very different set of values and life experiences, their combined lives take on a more dynamic, evolving turn which helps them to learn and grow as individuals as well as a couple. [Related: Is He Mr. Right or Mr. Right Now? How to Know if You Should Commit to Him]

In fact, a 2013 study found that when asked about the closeness between themselves and their partner, it wasn’t the couples who were most in sync or distant from one another, but somewhere in between, who had the most success in their union. Lead author of the study, David Frost, explains that, what really matters is not how close two people are, but how close they want to be. Simply put: most people wish to attain a level of intimacy with their partner that is close, but not all-consuming. They want to maintain a sense of self and identity outside of their relationship and this is hard to do if everything is similar between you.

How and Why Opposites Attract

But how, then, does this extend to the other side of the spectrum? Wouldn’t someone so vastly different from you be too distant?

The answer is no, actually, and for quite a few, interesting reasons.

As Linda and Charlie Bloom explain in their book, “Stronger at the Broken Places,” what most of us see as “opposites” are really “compliments.” Introverts vs. extroverts, impulse-driven vs. planners, always early vs. always late, these people, when drawn together, help to balance out extremes in the other’s personality. And, in many ways, people are drawn to their compliment because they recognize these dominant traits in themselves and wish to control them. The challenges that these contrasts of character create contributes to the dynamic necessary for long-term stimulation and challenge, which is what we all desire at some level. While we want to feel secure with our partners, we don’t want to fall into a rut and this happens more often when couples agree on everything.

The Law of Opposites
It all comes down to chemistry, and I’m talking about more than just initial attraction (though that’s important, too). After the physical assessment between two people passes, real “chemistry” is about having an instinct, a feeling about the other person which answers this important question:

Does my experience of myself seem more complete or whole with this person?

In a case when your own traits are simply reflected back upon you, the answer is “no”. However, when a partner challenges you to step out of your comfort zone, to reevaluate your beliefs and assumptions and defend your habits or predilections, the result is a much more fulfilling experience both as individuals and a couple. In this way Happily Ever After is not an end-game, but a point at which you realize that the challenge of your partner is as important as the security of your relationship and you become a better person as a result. [Related: How to Stop Dating Losers & Find the Perfect Man]