You may as well read the New York Times article about McCain and the lady lobbyist before you let others tell you what it said. All I'll tell you is that the article absolutely does not accuse the Senator of having an affair, so don't let anyone tell you that it did.
Having said that, one wonders about the timing of the story. It seems too early for it to be a Democratic hatchet job. The hot rumor is that the Times rushed it into print to beat a New Republic article that would question why the paper had been sitting on the story. If you want to think conspiratorily, you should ask who directed the former McCain aides to the Times or vice versa, and you shouldn't rule out the involvement of the Limbaugh-Coulter faction of rightists. Might not their hatred of Senator McCain be so great that they would desperately seek a way to drive him from the campaign even at the brink of victory? If he had to quit, and his delegates were freed to vote as they pleased, might it not still be possible for a candidate favored by the talkers to carry the convention? If you want to play the "who benefits" game, the winners would have to be the talkers and whoever they convinced to seize the nomination. BUT since the article does not accuse McCain of having an affair, and therefore doesn't have the potential to drive him from the race, you should speculate for amusement purposes only.