i guess you just know that the relationship is over - but it depends on wether people can admit it to themselves, many times a realtionship will be a dead one with neither parties wanting to be in that relationship but not knowing how to say so! Lifes get too tangled up together and it become hard to seperate!

but it also depends on what relationship your in - if marrigae ( in my opioion ) you should fight till your last breath to save you marriage! if its just a casual relationship then life is too short too be unhappy!