Ooooh! I can help here.

You've probably never heard of her, but I love the artist Annie Brooks. She's a Christian and is the step daughter of Don Francisco and daughter of Wendy Francisco, in case you're wondering.

She has one called Love Song which is based on the verses in 1st Corinthians 13, which is all about love. It's not necessarily about a guy and girl, but it's definitely about love. It's soft and nice, too.
She also has more up-beat ones. One is called Creme de la Creme, which is kind of slow, but not... and then there's Since You, which is nice and upbeat, but you probably don't want that for a wedding...
Her myspace page has a few songs to listen to for free, and you can find her on iTunes. I'm pretty sure she has some others you might want to listen to, but I haven't listened to her much recently and haven't heard all of her songs.
I think she's worth looking into, though.

Note: Sometimes Annie does wear short skirts and low-ish neckline (though not in my opinion...), so if you have a problem with real short skirts low-ish necklines, you might not want to look her up. Just thought I'd let y'all know.

EDIT: HEY! What do ya know? I found her first album for free online.

And, don't worry, it's not illegal. It's from her step-dad's website on the section of free downloads.
http://www.rockymountainministries.org/ ... aking.html VOILA! And, I couldn't remember the name to this song's name until now, but On the Other Side is really really good, too.

Rescue Me is done in the form of a ballade-type song. It's really cool. Highly recommend it for everyone on here.
Anyways, I hope this helps.