This news would probably have hurt John Edwards' campaign for president a lot more if... what... oh, right: If he were still running for president.
As it is, I think it's actually just an admission by a rich lawyer dude that he stepped out on his wife while she's battling cancer. Very classy.
UPDATE: Here's a kinda interesting blog post from last fall on MediaBistro's L.A. site that sheds light on Edwards' gal-on-the-side. Hint to future presidential candidates: If your potential affair goes by names as unsimilar as Rielle Hunter and Lisa Druck, she might cause trouble down the line.