Why do men NOT forgive an infidelity?

Without generalizing, it is common to hear that men do not forgive infidelity , suffer a couple betrayal, is a fact that goes directly to their pride, self-esteem and manhood.

In addition to feeling betrayed, men go through a great social, family and work pressure, since they receive reproaches of how they allowed their partner to be unfaithful, because if she betrayed him it is largely because he stopped doing something that it led to those circumstances.