Othello:Othello Act 3, scene 3, 263–268
Haply, for I am black,
And have not those soft parts of conversation
That chambers have, or for I am declin'd
Into the vale of years (yet that's not much),
She's gone. I am abus'd, and my relief
Must be to loathe her. O curse of marriage!
"Vale of years" shouldn't be confused with "vale of tears," although the echo is suggestive. A "vale" is a broad, flat valley; in the fifteenth century the word came to be a metaphor for the span of life between the peaks of birth and death—that is, life in this careworn world. "Vale of trouble and woe," "vale of weeping," "vale of misery," and "vale of tears" illustrate typical uses of the word before Shakespeare. Othello's phrase, however, seems intended in a more neutral sense; the "vale of years" is the broad, flat stretch of middle age beyond the slope of youth.
As Othello searches for reasons why his wife might be unfaithful to him—as his "honest" ensign Iago has all but convinced him—he thinks of his slow decline into the vale of years as one possibility. That he is dark-skinned, while his wife is white as alabaster, and that he thinks his "conversation" (discourse) coarse while hers is refined, are other possibilities, and they make Iago's accusations seem more likely. Iago has fabricated the whole scenario, knowing and playing on Othello's emotional and logical weaknesses.