So we are assured that Kumud is the ideal daughter-in-law: she wins the hearts of her in-laws; she never complains about her husband who is a bawdy boozer, and she sets out on a mission of redeeming him. A dharampatni!!!!!
She is aided by her ex-lover who knows nothing but "sacrifice" (who sacrificed his emotions and passions and became a sanyasi lest another woman surrender her life like his mother did; who sacrificed his honour and reputation to do penance for the gau hatya and thereby mitigate the pain he caused Kumud's family when he refused to marry her; who sacrificed his love and longings to see his ex-lover happy.
So it's the great lesson of sacrifice...sacrifice...sacrifice (the foundation on which a family survives) once again.