Unless he’s pulling a “McGreevey”, for every cheating man there’s a cheating woman. And women are just as capable of doing the “McGreevey” as men ... so that works both ways, too.
Your math assumes that the same number of women are cheating as men. It leaves out the possibility that men are having multiple affairs or at least more than women. There are societies in the world where the men carouse around while the women stay home and take care of everything. See the Italian siestas as an example.