Why Was Lord Rennard Removed?

Nick Clegg seems to be prevaricating over why Lord Rennard resigned. Was his health really the only major reason or not? Did Lord Rennard resign of his own free will or was he pushed with ill-health given as a reason. One way or another, whether Lord Rennard is guilty or not, I suspect the Liberal Democrats are in big trouble, and that Nick Clegg is especially in trouble