FYI: C.S. Lewis on Love

Love and Commitment C.S. Lewis, in "Mere Christianity"

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. The curious thing is that lovers themselves, while they remain really in love, know this better than those who talk about love. As Chesterton pointed out, those who are in love have a natural inclination to bind themselves by promises. Love songs all over the world are full of vows of eternal constancy. [This] law is not forcing upon the passion of love something which is foreign to that passion's own nature; it is demanding that lovers should take seriously something which their passion of itself impels them to do.

And, of course, the promise, made when I am in love and because I am in love, to be true to the beloved as long as I live, commits one to being true even if I cease to be in love (emphasis added). A promise must be about things that I can do, about actions: no one can promise to go on feeling in a certain way (emphasis added).

Being in love is a good thing, but it is not the best thing. There are many things below it, but there are also things above it. You cannot make it the basis of a whole life. It is a noble feeling, but it is still a feeling. Now no feeling can be relied on to last in its full intensity, or even to last at all. Knowledge can last, principles can last, habits can last; but feelings come and go. And in fact, whatever people say, the state called "being in love" usually does not last. If the old fairy-tale ending "They lived happily ever after" is taken to mean "They felt for the next fifty years exactly as they felt the day before they were married," then it says what probably never was nor ever could be true, and would be highly undesirable if it were. Who could bear to live in that excitement for even five years? What would become of your work, your appetite, your sleep, your friendships?

But, of course, ceasing to be "in love" need not mean ceasing to love. Love in this second sense--love as distinct from "being in love"--is not merely a feeling. It is a deep unity, maintained by the will and deliberately strengthened by habit; reinforced by the grace which both ask, and receive, from God. They can have this love for each other even at those moments when they do not like each other. They can retain this love even when each would easily, if they allowed themselves, be "in love" with someone else.

"Being in love" first moved them to promise fidelity: this quieter love enables them to keep the promise""