Sometimes, there is a choice between being a "good person" or being a successful one. Often, one can't be both. What is a "good person" anyway?

When members of any population (in this case, men) experience a scarcity of some essential resource (in this case, sexual access to women), the amount of sociopathic and deceptive behavior within that population in pursuit of the scarce resource tends to increase. That's just life.