During a broadcast of my show El Debate: Pensar México (The Debate: Thinking Mexico) I asked why does couple love vanish over time? Why is there more enthusiasm for seeing your significant other, more desire, more tolerance more resignation towards personal preference at the beginning of your relationship? Panelists not only answered my question, we received quite a lot of emails from viewers voicing their opinion. In general, we could classify their answers in the following manner:

1. At the beginning or a relationship people look for romantic love, which only prospers with novelty, mystery and danger and dissipates when novelty transforms into habit and what was mysterious becomes common encounter.

2. Being in a relationship not only implies sharing your life with someone, one of the main incentives when looking for a mate is getting pleasure. Bluntly put, intimate encounter. But the question is how to reconcile this initial desire with other characteristics of romantic love like compromise and admiration. Because of it, initial love tends to degrade towards friendship leaving passion aside or transforms into purely sexual encounter.

3. Romantic love disappears because it is inspired in the “man/woman of my dreams”, an ideal. We fall in love under the veil of fantasy, women search for their prince and men search for their princess but time leads to reality and disillusion.

4. The reason is that times change and people change. We yearn for stability in our relationship, but with time circumstances lead us to modify our interest, taste and preference. Without warning, we hear the phrase “you’ve changed a lot”. The fact is that many people want to fall in love to give their lives meaning. It often works, for a while.

There is some truth in each and every one of the previous explanations. Generally speaking, they coincide in that it is not a matter of romantic love having the tendency to disappear, but that we actually make the effort to degrade it. Evolutionary psychology could tell us why.

Throughout our evolution, human animals have been developing diverse strategies for survival and reproduction. One of these strategies is assuming risks. In the same way that fear is an instinctive lesson inherited from our ancestors to escape the clutches of a predator, taking risks allowed our ancestors to reproduce, gain power and experiment with a greater variety of prey, food, climate, environment, etc. Risk brought a diet richer in proteins, it helped human beings expand throughout the planet and obtain greater resources for survival and transcendence.

And like risk, adrenaline and danger are part of human nature; in another sense our instincts reveal the necessity of feeling secure.

While compiling date about divorce in different societies, anthropologist Helen Fisher found surprising patterns. The majority of people divorced around the fourth year of marriage, their age was around twenty five and/or they only had one child in their care. Coincidentally, some anthropologists—based on the observation of traditional societies with a lifestyle controlled by constant physical effort, a light diet and little weightgain, apart from long lactancy periods—suggest that four years is the habitual time that marked frequency of birth for our ancestors.

Considering the previous, Fisher sustains that across 3.5 million years the human animal learned to live with a mate, at least for four years, enough time for the offspring to have a certain autonomy. Throughout these millions of years they affirmed feelings of attachment and security, and the brain circuits that gave birth to the cumulus of emotion which we call love configured.

It is not a coincidence that the word “familiar” comes from “family”. The importance of bloodline, which gives us comfort, peace. Our nature demands certainty, familiarity, protection, in other words: the illution of stability.

Then on one hand we need adventure, risk, mystery, surprise and on the other we need stability, security and certainty. Anxiety doesn’t allow us plain reproduction but neither does it allow monotony, our brain is programmed to relive the adventure of romantic love.

The human animal needs both: security and risk, familiar and novelty. Sometimes we find ways of chasing this yearning in an alternate way, sometimes in delicate balance with the mate. Due to being pulled in opposite directions, a balance between security and risk can only be transitory.

Romantic love attracts with its promise of security. Nevertheless, love is not static “you cannot simply pause your instinct”, if you are satisfied with security today it’s because you took a risk a short time ago and maybe you will want to do it again. Romantic love is destabilizing by nature.

Based on the previous statement, the real question is not—as is manifested in the majority of literature on the subject—why do we fall in love?; rather how do we manage to stay in love?

The answer is the conception that the human being changes and in the process demands, on one stance to reinvent and recreate fantasies, passion and adventure with the significant other, while on the other stance, pro-healing, caring and offering stability in the space-time of security and certainty that our own nature demands. A fight between opposing forces, an equilibrium—that can, in fact, be achieved—has the best of both worlds; “passion and certainty, till death do us part”.