I don't think the the man is really running for President, he's selling his book. He never set up an organization, and he seems more intent on trying to sell his book than actually campaign.
I have no problems with a politicians sleeping around, but when you seem to have a history of sexually harassing woman, that says something about your character, and who you are. Not like it would have mattered to me though, as there's no way I would ever have voted for him. Cain's response to all the allegations are also just making it worse, because he keeps changing his story, and blaming the media for "accusations." As Jon Stewart pointed out, the media is not making allegations, they are reporting other peoples allegations.