A wonderful anthology of poetry and prose on love and marriage that Garrison Keillor recommended to a listener in his post to the host.  Here is his response: 

For a wedding poem, I recommend that you consult an anthology edited by Robert Hass and Stephen Mitchell, called Into The Garden: A Wedding Anthology which has texts from various religions and poems and lyrics, all of them suitable for a wedding ceremony. I love the Yeats poem (so short you could say it yourself to your true love) — Wine it comes in at the mouth, and love comes at the eye. That is all we know of truth 'fore we get old and die. I lift the glass up to my mouth, I look at you and sigh. — There is Robert Burns's "My love is like a red, red rose" and "A Blessing" by James Wright, good especially if you love horses. There are many good E.E. Cummings poems, including "Since feeling is first, who pays any attention to the syntax of things will never wholly kiss you" — and of course there is "Come live with me and be my love".