What is love?

Lately, I have been observing a few couples around me and I deduced a pressure-mechanism which actually stimulates couple to be more loving.

I realized after the initial honeymoon stage, many of them start to show signs of "relationship that won't last". However, over the years, when couples age, people around start settling down, they suddenly feel that they have to recreate this passion once again. And suddenly, I see couples who were dull and boring suddenly comes to live....

My question is, what actually made them want a come back? Are these real love? Or are they merely building it up for the future. Are they just satisfied with one another? Why should you just be satisfied with what u have? Shouldn't you get the best in terms of wanting to give all your love to?