The problem is that Trump does not seem to realize he is in a political campaign. What worked for him in business when dealing with someone making an accusation about his personal life doe not work in politics and as a matter of fact it 180 degrees from what he need to be doing politically.
Trump learned that if he was attacked that treats to sue, intimidation, and hitting his accuser back with his own Trumped up allegations worked and they would go away.
Don't often have anything good to say about politicians but Trump needed to learn, before he started the campaign, at least a bit of practical political judgment.....