I like to think that you hear more stories of men cheating because men are more reserved and they tend to not say anything about what happened. Where as women tell their girlfriends everything. And to an extent a man telling another man that his girl cheated on him. Is like basiscally saying I let my girl disrespect me and men tend to hold an ego in front of friends.
I think if men where more open it would be the women that cheat more because i have been in a couple of relationships where my girl cheated on me. And I have never cheated on a girl ever.