Ensign Backs Off Extortion Claim?

Sen. Ensign’s out-of-the-gate story was that the husband of his former mistress was extorting money from him. That seemed questionable since extortion is a serious felony. And generally people get arrested for it — which didn’t seem to be happening with this guy. Now Ensign seems to be backing off that story.

If he made it up, why did he come forward now? And if so, does he take heat for a false charge?