Searching for arnav khushi ss or ff

i am searching for arnav khushi story were khushi n arnav get engaged khushi is lavanyas sister in starting khushi was emplyoed as fashion designer in ar khushi was free lancer before that khushi is a adopted child of lavanyas parents when the rishta came lavanya thought it was of arnav but it was of Akash sh who is arnavs elder brother who already has a son