As most of us know, our bodies can be broken down into simple chemistry. The same is true for how things react in our brain. It was interesting to learn that in this study people who had been in long term relationships of an average of 21 years had the same chemical reaction in their brains as people who had recently fallen in love when they were shown a picture of their partner. What's also interesting is that an activity jump in the areas of the brain associated with maternal love and pair bonding suggest that feelings of attachment are an important facet of a romantic relationship, at least as demonstrated by the chemistry in your brain.
Obviously the key to a long term relationship is not just mere chemistry...science has yet to figure out exactly what keeps the flame of love alive for extended long term relationships, but we all know it's more than just romantic love. A healthy long lasting relationship also requires elements of attachments and pair bonding and I submit, cooperation, honesty, communication and respect for one another.
Selected excerpt(s) and linked article courtesy of Grace Browne, Inverse