Cheating
Cheating (also called gulling) is an act of lying, deception, fraud, trickery, imposture, or imposition. Cheating characteristically is employed to create an unfair advantage, usually in one's own interest, and often at the expense of others

As we may assume, the motivation for women is sometimes different than the motivation for our male counterparts.....

Top ten reasons why women cheat
Revenge for your cheating
Exit strategy
Bedroom boredom
Your emotional withdrawal
Feeling neglected/ignored/underappreciated
Lack of intimacy
Revenge/payback for past wrongs
Self-esteem
Being the bad girl
Not enough sex
Top ten reasons why men cheat
You don't love her anymore
She doesn't turn you on anymore
Women let us
Your girlfriend is a nag
The opportunity was there
It boosts your ego
You can get away with it
It's challenging and exciting
She cheated on you
Your lady doesn't put out