The noblest relationship is marriage, that is, love. Its nobility resides in its altruism, the desire to serve another beyond all the pleasures of the relationship; and in its refusal ever to regard the other as a thing, an object, a utilizability. Sex is an exchange of pleasures, of needs; love is a giving without return. It is this giving without return, this helping without reward, this surplus of pure good, that identifies the uniqueness of man as well as the true nature of the true marriage. This is the quintessence the great alchemy of sex is for.
John Fowles

There is no lonelier man in death, except the suicide, than that man who has lived many years with a good wife and then outlived her. If two people love each other there can be no happy end to it.
Ernest Hemingway

Triad, Jefferson Airplane