My Husband's Wife is a film about an Indian Sikh family settled abroad, wherein the grandfather Kartar Singh (Prem Chopra) migrates forty years ago. He starts his career as taxi driver and when his son grew up, his business turned into multi-millions. However, he always remains attached to his country India. His culture, sentiments and emotions makes him get his son married to a Punjabi girl (Rati Agnihotri).
His daughter-in-law gave birth to a beautiful son (Pawan), but unfortunately Kartar Singh's son dies young. Kartar Singh gives the best of education and amenities to his grandson with a kind of love and affection. However, the grandson becomes a Playboy even though he respects his grandfather as well as his mother. The culture of the west hypnotizes the grandson.
Seeing the circumstances, Kartar Singh decides to get his grandson married to an Indian Punjabi girl (Rakhi Vohra), thinking that the wife from India will show him the path to live life as an Indian. The grandson starts handling the family business with sincerity and does well. But his wife from Punjab shakes him up in terms of his preference to western culture.
He goes back to his earlier girlfriend (Alisa Khan) and starts drinking heavily. The emotional drama between the grand father, mother and the wife starts from here. How the second woman is the wife's husband's wife is justified is the culmination of this emotional saga between the loves of two women torn for a single man. The values and the emotions of Indian culture win the heart of everybody and the blessings of God showers on the family.