"Letters of Note," a fairly fascinating blog of unearthed correspondence, happened upon some letters Johnny Cash wrote to his wife, June Carter Cash, and they're really something. The first one he wrote in 1995, on her 65th birthday:

Happy Birthday Princess, We get old and get use to each other. We think alike. We read each others minds. We know what the other wants without asking. Sometimes we irritate each other a little bit. Maybe sometimes take each other for granted. But once in awhile, like today, I meditate on it and realize how lucky I am to share my life with the greatest woman I ever met. You still fascinate and inspire me. You influence me for the better. You’re the object of my desire, the #1 Earthly reason for my existence. I love you very much. Happy Birthday Princess. John

The second one he wrote to her shortly after her death and, well, you should really just go read it for yourself. Grab a hankie ...