If Laajo hadn't married Nikhil then they would not have needed to avoid having guests in their house and therefore Nikhil would have had no reason to leave the house. It's like a domino effect...
With that reasoning then, one could say if she never married Inder than Akash (who of course would not exist in the first place) would not have gone to the village to visit his grandfather and therefore would not have fallen off the roof... But of course we could just keep going back and saying if she hadn't married Inder then Akash would not have existed, therefore she would never have to face the pain of losing her son. Or better yet...if her mom didn't have her none of this would happen and so on and so onđ
Does fate have nothing to do with this? It was an accident (both were). She can't blame Laajo for Nikhil's decision to leave. Just as she can't blame Nikhil and Baba for Akash's death...