Could it be Arjun who suspects that Purvi is pregnant with his child? If he blatantly asks her, its obvious that she will deny. She's obsessed with keeping Ovi happy... So in order to find out the truth, he takes the crooked path and pretends to blackmail her. If she agrees to his demands, then his suspicions will be confirmed...
Seriously, doesn't anyone else like the Purvi-Onir Jodi??