Badaltey Rishtey (1978)

Sagar Singh is a businessman who lives in scenic Simla with his widowed mom; brother, Bipin, his wife, Urmila; sister, Prema; and brother, Kishan. When he returns from USA, he meets with Prema's music teacher, Savitri C. Thakur, and falls head over heels in love with her. The Singhs approve of Savitri and soon the couple are married. What Sagar does not know is that Savitiri loves another man by the name of Manohar Dhani, who is the local tourist guide, but cannot marry him, as according to an astrology professor her husband is fated to die within the first 40 days of her marriage. She keeps her affair a secret from Sagar, but Manohar shows up - and he makes his intentions quite clear from the beginning - that he is here to marry Savitri, by hook or by crook, even if he has to kill Sagar, if necessary.