One of my favorite fairy tales when I was a kid was The Singing, Springing Lark (and its numerous variations as I ran into them). If you're not familiar with it, it's like a cross between Beauty and The Beast, and Eros and Psyche.
The basic plot is about a girl who has to marry a mysterious/beastly suitor. Fortunately for her, he turns out to have an optional human form and they live happily together for some time.
Eventually she wants to go visit her family, and she wants her husband to come with her. He reluctantly agrees, but warns her that if candlelight/daylight touches him she will lose him. Sure enough, the worst happens; he is transformed into a bird and flies away. The only way she can get him back is to commit to a difficult journey, involving things like bleeding feet, iron shoes, and either a set distance (thousands of steps) or time (years and years of walking).
Without a second thought, the bride takes off to follow her husband, determined to win him back no matter what sacrifice might be required of her.
"I walked ten thousand miles, ten thousand miles to see you,
And every gasp of breath I grabbed at just to find you,
I climbed up every hill to get to you,
I wondered ancient lands to hold just you.
And every single step of the way, of pain,
Every single night and day,
I searched for you.
Through sandstorms and hazy dawns I reached for you."
The Sore Feet Song, Ally Kerr
Music: The Sore Feet Song, Ally Kerr