Each relation in our life is like paving cement onto the ground
and your love is like the person crossing it. No matter how careful
he/she walks - it will bound to leave marking on the cement.
People *DO not* forget relation, although many chose to let it pass
and get on with their lives because simply if they don't, they also
cannot do anything about it most of the time. So the only option is
to move on, than to stay in this pit of sorrow. 
People remember relation especially, the woman/man you *feel* you
most loved *at that point of time*, first love, love that was never
meant to be yours (you yuan wu fen kind), the unattainable, you did
all you can, but it doesn't turn out the way you want, the
man./woman that is so different and you so loved it and you know
that you will never find another person the same, and the lists
goes on.
Noticed a link between all these? Yes, you guess it: You remember
most deeply is relations you can never have or once had and lost
it.
Here is another analogy.
Imagine one day when you were out shopping in a super market and
you wanted a drink. You saw a new drink and decide to try it out.
You paid about a dollar for it, walk out and happily open it to
drink it, just to find out that the drinks sucks. You threw it away
and cursed.
Who will complain and rant over such small priced items over the
course of 1 month?
A change of location: Imagine you wanted to buy a Handphone, some
latest one (perhaps 6110). Only after you bought it, you found that
it is damn sucky.
Chances are, you will complain, rant, and *feel* the pinch of the
money spent and it's not worth your money even after one
month.
So what am I talking about?
The more money you spend buying one item and to find out that its
not what you want - the more you will feel the pain: In relation,
the more you give and contribute (mentally, emotionally and
spiritually) in this relation and it doesn't last - the more you
won't forget and longer time you need to heal the hurt.
ONS is like buying a stick of sweets that cost 60 cents - you don't
give a sh|t even if you don't like it - life just move on.
After naggy so long - my answer to your question is: You want to
know how long you need to heal the pain? So how much have you
'spend' then?
Cheers
