why would he lie?

He says he's been with over a hundred women.. I'd believe it if he knew what he was doing in bed. Doesn't even know where the clit is and how to flick it. It's painfully obvious he is not telling the truth. It doesn't piss me off it just leaves me with why would he lie? I honestly suspect it's because he has a very small penis and he's just the ego-type guy. what's your input, ladies?