Dirty Science Friday: Why New Love Only Lasts Two Years

Hedonic Adaptation is the Reason for Your 2 Year Boner Window 

Evolutionary forces are at work affecting our physical attraction to a partner over a long period of time. For those interested in creating long term, monogamous relationships, understanding our hardwired trajectory of sexual desire and sense of happiness can be crucial. Hedonic adaptation is the scientifically studied aspect of human nature in which no matter how many positive thing happen in our lives, we find equilibrium and revert back to being just OK. As Sonja Lyubomirsky writes in The New York Times: 

We move into a beautiful loft. Marry a wonderful partner. Earn our way to the top of our profession. How thrilling! For a time. Then, as if propelled by autonomic forces, our expectations change, multiply or expand and, as they do, we begin to take the new, improved circumstances for granted.

Even more so than the waning thrill of moving to a new city or that garbage iPhone 5S that you hope gets stolen, physical attraction is particularly susceptible to Hedonic adaptation. A 2003 study conducted with 1,761 people over the course of marriages lasting over 15 years shows that by far the first 2 years are the happiest. After that, the study shows, life just goes to shit. JK! It is, however, impossible to maintain the same level of intense attraction you had for somebody as when you first met. While that desire evolves into a different kind of (often more sustainable) love, that insatiable thirst for a lover's hole is inevitably quenched. Unsurprisingly this touches on why people cheat, why people search for increasingly interesting things to do in bed, and why Helix Studio models have a shelf life of 5 minutes.

While relationships change after two years of swinging from the rafters, they don't end. Lyubomirsky:

When love is new, we have the rare capacity to experience great happiness while being stuck in traffic or getting our teeth cleaned. We are in the throes of what researchers call passionate love, a state of intense longing, desire and attraction. In time, this love generally morphs into companionate love, a less impassioned blend of deep affection and connection. 

Although sexual desire changes over the course of a relationship, there are practical reasons for a decline in that tingly butthole feeling, and even the possibility of a redeeming late-in-life fuck renaissance. The evolutionary reason for a wan in sex drive with a monogamous partner is that we wouldn't get anything done if we always had our mouths full of each other's balls. I mean we couldn't even talk for goodness sake. The change from passion to "I thought you said you were going to pick up some milk" allows us to live our lives without the distracting haze of wanting. We settle into something more comfortable in which desire is no longer the foundation of the relationship. 

The redeeming part of Hedonistic adaptation is that with significant changes, you can reset sexual attraction and achieve some of the magic from the first 2 years. In a study, couples experienced a revitalized sex drive particularly when their kids left home for college. When left alone after so many years with other people in the house, couples could once again find surprises in each other. I'm interested to see how this, in particular, affects gay couples as more and more of us have children over the upcoming decades.

My takeaway from all of this is: Relax. There's a lot of anxiety tied up in how sexually attractive we are to our partners. While this article mentions two years as a specific changing point in dynamics, thinking about Hedonic adaptation's influence on relationships tells us that there are deeper, shall we say scientific, forces at play - most likely dictating a rang of ebbs and flows in sexual desire between two people.  

Via The New York Times 

Image: David Hockney's Domestic Scene, Los Angeles