“[Syme had a] sense of a new comradeship and comfort. Through all this ordeal, his root horror had been isolation, and there are no words to express the abyss between isolation and having one ally. It may be conceded to the mathematicians that four is twice two. But two is not twice one; two is two thousand times one. That is why, in spite of a hundred disadvantages, the world will always return to monogamy.”

G.K. Chesterton, from the novel The Man Who Was Thursday.
A somewhat backhanded tribute to marriage, but a sincere and unromanticized one.