I assume you meant to ask if John wrote the song about their relationship -- obviously Elaine didn't write any lyrics -- but without knowing John personally I can only point you to what he's said in interviews. In the liner notes to "On The Rural Route 7609" he said that "Forgiveness" "might be sort of a love letter to Elaine." He spoke about it even earlier in an interview from 2007, right before "Freedom's Road" came out. This is just a portion of John's answer, the full interview can be found here:
http://www.mellencamp.com/forum/index.php?topic=752.0FOR ME "FORGIVENESS" RANKS ALONGSIDE "HUMAN WHEELS" AS ONE OF MY
FAVORITE MELLENCAMP TRACKS, HOW DID THAT COME ABOUT?Since it's right in the middle of the record, it's sorta the theme of
the entire record. All of the things that we've done, and all of the
things that we will do. I've been married 15 years to my wife, and if
she wasn't so forgiving, I probably wouldn't have been married that
long. It's her ability to forgive, and in a marriage it's always
kinda nice to have somebody that's got a big heart, and can forgive
and also is a little blind.
thanks walktall that was some article. i did a little research (i really like that song) and i came across this article and found it quite interesting you can read it here
http://www.menshealth.com/best-life/rock-solid