So i found these explanations n wanted to share it wit u ppl:
When a woman marries a man she signals to the world her new IDENTITY by changing her name to her husband's. Through this action she acknowledges God's new creation - 'The Couple' and thanks Him for bringing her husband and herself together. Upon marriage she enters into a covenant between her husband, herself and God. She becomes part of something greater than herself: a union blessed and created by God.
and sid indeed has become a part of ridhhima's identity now!The above explanation was from a religious standpoint n this one's from a psychological POV:
"The married change-name is, among other things, a psychological act, an imprinting by society on the (bride-bridegroom) initiate's consciousness. A newly-coined married name encodes new information about the man or woman. It connotes primarily that a new social relationship has occurred. A new name is a symbol of allegiance to a new person, a new nexus of relations, a starting-over."
I guess this is what ridzi meant wen she said Abb Main Ridhhima Gupta se Ridhhima Modi bann chuki hoon!