I agree that Ennis absolutely is the one I think of when the song plays over the end credits. Especially the haunting lines:
Everytime I think of him,
I just can't keep from crying.
and then
I stole away and cried.
Never had too much money,
never felt quite satisfied.
You can just see Ennis sitting in his trailer at the end of the day staring out that window, tears in his eyes as he thinks about his lost love.
I had been trying to think about song placement throughout the scenes. Some songs just don't seem to make sense where they are positioned. Then it sort of hit me -- when the two are together we get all the beautiful and peaceful bridge music. Everything is good (or relatively).
Then when the two are apart we get all the beautiful ballads and songs of loves that will never grow old and not wanting to say goodbye. When the two are apart, they have all the misery and anguish of being separated. And the music reflects that. Even when Jack is dancing with Lureen when he meets her -- the second song is a slow one ("Noone will Love You Like Me"). He pulls her close and then looks off in the distance and has the saddest look on his face. He had not even had his reunion yet, but he was thinking of Ennis.
I play the soundtrack everyday. It is a little bit therapy, and a little bit of an opportunity to stew in the juices of all the emotions from the movie. I still have moments where I just want to break down and cry myself.