One of my really good friends just started a 'cause' on Facebook to encourage people to support their friends' marriages and the covenant of marriage. The success or failure of a marriage is ultimately up to the two people involved in it, but strong support from friends and families is a large part of the equation.
Amanda is really putting a lot of herself into this (read the extended info and her story in the discussion board). I've gone through similar problems and was lucky enough to have some friends that stood by me and pulled me back to Christ and my wife, and I can remember when she was considering divorce. It is really good to see her reaching out to help others now.
If you are on Facebook, please join the cause and tell all of your friends about it. Link to I SUPPORT YOUR MARRIAGE: http://apps.facebook.com/causes/281509
She is also looking for ideas to help grow the cause. Message her if you have ideas - she is listed as the admin of the group or let me know and I can pass it along.