The fading of our lust is also a strategic evolutionary move. Our “addiction” to our partner keeps us around long enough to have a baby and raise him or her together until the child is around four years old, old enough to be somewhat independent (at least on the ancient savanna) and survive. Once our work there is done, lust fades, and our brain frees us to create new children with new partners, increasing the chance that at least one of our children will live to adulthood and carry on our DNA.
