This will definitely not end the campaign. The story itself isn't that much different than a previous story the NYTimes reported:
http://www.nytimes.com/2016/05/15/us/politics/donald-trump-women.html
But the combination of Trump losing almost a billion dollars in a strong economy, poor debate performance, and whatever other controversies he's drug up this week (didn't he tell people to watch a sex tape?) are definitely not helping him. If he somehow has a bigly performance during the debate(s), and there's a leak that seriously damages Clinton, he could theoretically rebound. Thankfully his chances of winning are slim at this point, but his campaign is definitely not over yet.
I just don't see why
this would be the thing he said that pushed undecideds away from him. Like, I don't think it even ranks in his top 10 most disgusting.