When you fall in love, you tend to take advice from your significant other, even when it's not totally clear that they know what they're talking about. Case in point: Carrie Underwood and her husband Mike Fisher were reading The Purpose Driven Life, a self-help book and 40-day spiritual journey exercise by Rick Warren, together when he suggested she write a song called "Temporary Home."

The idea wasn't clear to Underwood at first, but she kept it in her metaphorical back pocket and continued to mull it over. Then, shortly before a co-writing session with Luke Laird and Zac Maloy, the idea took shape.

As it turns out, Fisher had a really great idea: "Temporary Home" became the second single from Underwood's third studio album, 2009's Play On, and earned Underwood her ninth career No. 1 song. The track was also nominated for a Grammy (Best Female Country Vocal Performance) and at the Inspirational Country Music Awards.

Below, Underwood recounts the story behind "Temporary Home," in her own words.

They're not exactly easy words to sing when you think ... "Temporary Home." It doesn't sound like a song to me. But I bounced [the idea] around in my head for a couple of days: "Maybe I can incorporate this somewhere. I don't know."

I was getting ready to go in to write with Luke Laird and Zac Maloy, and it just hit me like a ton of bricks, just a flood of words and stories. And all of a sudden, I thought of a little boy in a foster situation, and he knows where he's going, and the place where he is isn't where he should be, but he'll get there someday. So in the meantime, he's just walking through this space.

And then the next story was, of course, about a young mom who was in a halfway house situation: really struggling, really trying, still confident that she wasn't where she belonged, but she was headed there. [The man in the third verse is] on the way to where he's going: He's on his way to Heaven; he's on the way to be with God, and everything that he's lived through was wonderful, but this earth was just his temporary home.

And when I went in and started talking to [the co-writers] about it, they were all about it. So, it came together pretty quickly ... three different situations, but still very positive that they're confident where they're headed and where they've been, and they're happy about where they're going.

Stuff kind of changed around and never ended up the way it was until we were done with it. Then it was like, "Oh my gosh! This is pretty amazing!"

Somebody can listen to [Play On] to get more of a sense of who I am, and they can listen to certain things and [think], "This is really sincere, this is really emotional, and this ... she was a writer on it, this comes from something that is deep inside of her heart." And I do feel like people can get to know me a lot better from Play On.

This story was originally written by Donna Hughes, and revised by Angela Stefano.

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