The Greeks divided the idea of love into “eros,” fileo,” and “Agape.” The concept of “eros” is not found in the Bible though, fileo and agape are. These latter two terms tend to be used for brotherly love and a divine love. It is usually common to make a sharp distinction between these two terms, but in reality the Greek New Testaments seems to use them interchangeably. The idea of love has been a pervasive concept in poetry and philosophy alike. As a result it has tended to be misused in certain contexts.
For Lewis, the idea of love was an insufficient reason for the maintaining of marriage. He writes:
The idea that “being in love” is the only reason for remaining married really leaves no room for marriage as a contract or promise at all. If love is the whole thing, then the promise can add nothing; and if it adds nothing, then it should not be made.
Professor of Ethics, Dr. Mark Ross, illustrates that if marriage does not resemble the sacrificial love of Christ for His bride, then every reason given for sustaining a relationship is futile. According to C.S. Lewis, the idea of “love” should never encapsulate our entire marriage relationship. There is also an element of a promise or a vow, by which both partners can look upon with security knowing that this is meant to last a lifetime. Our modern commitment to marriage is a horrific demonstration of how Christian virtues can be influenced by secularism and romanticism– both fatal philosophies.
 Some add a fourth word storge. It refers to natural affection in Modern Greek.
 Mere Christianity, pg. 98.