I love "I Like You" by Sandol Stoddard Warburg. It's a children's book, and it's very sweet. I think it would make a perfect reading to include in your wedding ceremony. Here is the full text:
I like you because when I tell you something special, you know it's special
And you remember it a long, long time.
You say, "Remember when you told me something special?"
And both of us remember'
When I think something is important you think it' important.
We have good ideas
When I say something funny, you laugh
I think I'm funny and you think I'm funny too'
If you find two four-leaf clovers, you give me one
If I find four, I give you two
If we only find three, we keep on looking
Sometimes we have good luck, and sometimes we don't'
Even if it was the 999th of July
Even if it was August
Even if it was way down at the bottom of November
Even if it was no place particular in January
I would go on choosing you
And you would go on choosing me
Over and over again