Just a couple of random thoughts...
1. What if Shivaay finds out Daksh is the stalker and doesn't have much time to explain things to Anika and hence forces her into the marriage.2. He has another misunderstanding that Annika has joint hands with Daksh to destroy his family and hence he does this.. but that doesnt make sense why would he not hand them over to the cops or something.3. Shivaay has initiated the marriage Annika looks more hurt than angry.. Shivaay looks angry.. so something has happened that has pushed his hand.. he is definately angry with Annika.