Sometimes when children are confused, and cannot foresee their future, then intervention MUST occur. Riddhima's weeping and oscillation at the moment will make her life more miserable, and she will not achieve two cents, thus the re introduction of the father to show the path to the daughter is essential. Riddhima is in a sacred bond, and currently there's miscommunication between Siddhanth - Riddhima, thus Shashank wants them to stay in their relationship for a few more months until they take upon a decision. Why shall they be forced to divorce, and why shall they take upon hasty decisions? Marriages are always meant to be worked out, but if in the end all fails, then any step should be taken forward, the same shall happen here. Riddhima has garnered sentiments for Siddhanth and Siddhanth is her silent lover, however both are unable to convey that to each other unfortunately due to the circumstances.
Shasank is just the catalyst here, and he isn't forcing his daughter to be under an unsatisfying relationship. Riddhima needs a chance to realize what her marriage may have in store for her, thus, Shashank is there to guide her. If of course she wants to walk out of the marriage in the future, she can, but she'll have no regrets for her marriage and the relationship with Siddhanth she shared.
Shashank is the catalyst here, and get ready to witness the greatest love affair post marriage. đ„ł