It is something we should have for all people, though, of course, we should have it to a much greater degree for the one we marry. You may think that this is not what you are interested in. You are interested in romantic love for a particular person. But unless you have agape as a foundation, the other loves will not last. Marriage will only stand the storms and stresses of life if it's built on the proper foundation.
Most people today build a relationship on erotic love as the foundation.
Usually the marriage cannot endure the storms that are sure to come. A couple discovers too late that true love cannot be built upon erotic emotions that erode with time. I remember a couple of young adults who were married. There was a big wedding all the trimmings. But the marriage only lasted for a couple of months.