"All is fair in love and war" refers to expectations in other people out in the world. You cannot expect for someone to treat you the way you would have treated them. If you don't have expectations of anyone in the world, whatever happens, you won't feel disappointment because you never had any expectations. This applies to women, and any other people you come across in the world. You will also avoid falling into the victim mentality if you don't have expectations from the get go and hold yourself responsible for most things that happen in your life. No one owes anyone anything in this world. The only thing that we can expect in this world is for our family to love us unconditionally, and even then many people in this world don't even get that. In my opinion this is what "all is fair in love and war" means. It means that life is unfair in general and that whatever happens it is all fair because life is unfair. If you're a kid on the playground and you push another kid on purpose and you are now at war, if the other kid kicks your butt you can't go home crying that someone beat you up, because that is the nature of war. In love, none of us are entitled to any person no matter how much we want them. Man and woman are both trying to get what each needs so you can't always expect to get what you want with other people. Love is a game in this context.