about love and war

they claim that all is fair in love and war, but I need an answer to this: In affairs of love (and war), when is letting go a strength?? and when is it a weakness?? Does hanging on mean that one is too weak to let go and move on?? or that one is strong enough to admit one's feelings and to hang on to a (non-existent) glimpse of a hope??? Or is it -just like most things- another gray area??