I happened to pick this question on a friend's blog and I guess we all have a lot to say in answer to this question.
This is what I said: "As long as you wish it to. I guess its more about if you've had your fill. If you haven't, your ego [read love sick self] will keep pulling back all those shards of memories of time bygone wherein the entire idea of love translates to longing for fulfillment. If you have had your fill, as in properly reciprocated, then it lasts as long as you can remind yourself of your need for that particular love."
I am making a note here, because this is what I feel at this very moment, in all honesty. It is subject to change surely and I shall look to a day when I would want to erase this thing up and write something else in its place. It might be contradictory then or I may continue to think the same but I am making an exercise in a reality check. Erm, whatever! This is for myself. I'd like to hear what you have to say too :) Do leave a note. :)