I am actually having second thoughts thinking he is after the child. If Sameer wanted he could have killed Shika just after Manav's birth and if any one would question him. He could have said it was labour problems or something. Why would he kill after 2 years when Maanav recognizes her and even calls her mum. No no he probably wants revenge of some sort like Shika's not so good past with Madhumira?
Agree but blowing up the house with no explanations will not let her know why and the reason behind his actions, so the reason of sticking it out so long would make no sense...