Why do women have to change their lastname after marrige ?

To me, name is a part of my identity.
Every person should have the right to change it on her/his own wish,
or if it is necessary. But after marriage, do we really want to lose that piece of our identity?

I am 2 years married and have adopted my husband's lastname.
but deep inside my heart i have a desire to still continue with my orignal name .
The name which represented me all these years and suddenly one fine day since I got
married I had to change my name.
My new name still seems stranger to me , as if its not my name but somebody else's name.

Ours is a love marrige , before getting married during our courtship .I used to feel happy just
by an idea of being called by my Husband's name , that was all fantasy ..
practically its a real pain to change your name ....saperating a part of your identity ...