I think there were a lot of very brief affairs, over a number of years. He "only" had four women on the line when he met the author. Assume the average duration of an "affair" is four months, stringing on four at once, works out to one new affair a month, so a little over ten years to hit 130. Sounds expensive and exhausting, but if you have the money and stamina...
Bet he paid nothing. Women give it away for free to men they find attractive while making demands of men they feel they're settling for.