The Christian idea of marriage is based on the biblical description of man and woman becoming one flesh - a unified, single organism. It is not meant to be mere sentiment or a beautiful expression, but rather a fact about the human nature. Just as "a lock and its key are one mechanism, or a violin and a bow are one musical instrument, the inventor of the human machine was telling us that its two halves, the male and the female, were made to be combined together in pairs, not simply on the sexual level, but totally combined."
The Christian views sexual union as a part of the whole union that man and woman experience together, so to isolate the sexual part from the rest is just as strange and unnatural as if someone isolated the pleasure of tasting foods from the entire process of eating and digesting them. This is also why divorce is such a problem for the Christian because it is more like surgically cutting up and dividing a unified organism than merely a change of partners or readjusting spouses when someone falls out of love.
We have learned from books and movies that...
- ...if we simply marry the right person, we will go on being 'in love' forever. And when that turns out not to be the case, we think we have made a mistake.
But the thrill we have at the beginning when we are 'in love' is meant to give way to a quieter, more sustainable and meaningful kind of interest. "If you decide to make thrills your regular diet and try to prolong them artificially, they will all get weaker and weaker, and fewer and fewer, and you will be a bored, disillusioned old man for the rest of your life. It is because so few people understand this that you find many middle-aged men and women maundering about their lost youth, at the very age when new horizons ought to be appearing and new doors opening all round them. It is much better fun to learn to swim than to go on endlessly (and hopelessly) trying to get back the feeling you had when you first went paddling as a small boy."
- ...falling in love is something we can't resist, something involuntary that just happens to us, "like measles." So if we are attracted to someone new, we feel this must mean we ought to throw in the towel on our marriage.
But while we ought to admire things like beauty and kindness and intelligence when we find them in others, and while it is perfectly fine to love those good qualities when we see them, isn't it "very largely in our own choice whether this love shall, or shall not, turn into what we call 'being in love'?"
But on the first point, which actually once again has a great deal of relevance to our contemporary American culture, Lewis says this:
"A great many people seem to think that if you are a Christian yourself you should try to make divorce difficult for everyone. I do not think that. At least I know I should be very angry if the Mohammedans tried to prevent the rest of us from drinking wine. My own view is that the Churches should frankly recognize that the majority of the British people are not Christians and, therefore, cannot be expected to live Christian lives. There ought to be two distinct kinds of marriage: one governed by the State with rules enforced on all citizens, the other governed by the Church with rules enforced by her on her own embers. The distinction ought to be quite sharp, so that a man knows which couples are married in a Christian sense and which are not."