Country song with gray hair in the lyrics?

Looking for the name of a country song that has something about gray hair in the lyrics. It's not a super new song, so it's not overly played on the radio but that's where I heard it (I'd heard it before but now it has meaning). It's a guy singing about a girl and about loving her when her hair turns gray or something along those lines. It's not Brad Paisley's Then, nor is it "don't change". I tried googling but am having no luck jogging my memory. Help! Trying to make a CD for a 40th bday gift by tomorrow evening!!! Thanks!