I'm sorry, but I do understand. As "pro-marriage" as we all are around here, sometimes it does get to a point where it's a matter of personal integrity for you.
Just let go, and lean on God. Instead of asking Him to "shorten your days," pray for Him to show you what HE would have you be doing in your life. Many men find great purpose at this stage of their life, and perhaps there is something far greater planned for you, and she was holding you back.
Just food for thought, but mostly just a man-hug of support.
