The wristwatch became popular with men shortly before as they were given to soldiers at the very end of 1800s. Previously seen as an accessory only for women, the use of watches in war (as it wasn't practical to pull out a pocket watch) made them eventually become fashionable.
That said, the watch produced for Santos-Dumont by Cartier did become the first widely available watch for men, and is still on sale today, in a more modern form: http://www.cartier.co.uk/collections/watches/mens-watches/sa...