Now here the story is similar the only difference i think (i m sure) that suhani is not nachiket's biological daughter but still he decided to take up her responsibility after roopali's death (her death due to ragini according to nachiket) This must have created problem for ragini as she must be thinking of suhani as nachiket's biological daughter and thus have denied him to do so. But the damage was done and they got divorced. And now Ragini is saying dat suhani is responsible for their divorce...So yes this behaviour of her is definately justified in the movie.