Please help me out

As you all know I don't follow the show but I love to write stories,so please can someone tell me in detail why Shivika are separated and what happens after Ragini enters? Because I want to write something on that plot

Pinky does not like Anika and doesn't want Anika to be with Shivaay. She blackmails Anika to leave the house or she will disclose the truth to shivaay that he is an illegitimate child. Anika therefore behaves insanely horrible with Shivaay. Shivaay plans to marry her again , the day he proposes her , she before the media says that Om is illegitimate and misbehaves with pinky and dadi. Shivaay is heartbroken. He throws her out of the mansion. Shivaay accidently hits Ragini on the road while driving. He brings her home and gets first aid for her. They become friends. Ragini wants to be with Shivaay and therefore is spinning all wild stories to make him fall for her.

Pinky starts feeling insecure after Anika takes a bullet for Shivaay and her cares for her, though dadi advices her but she doesn't listen. When Gauri and Om are to be remarried dadi insists on Shivika rasams too . During one of the rasams Pinky create problems and tells Anika Shivaay is illegitimate and If she tells him this he'll be shattered as Naam, Khoon khandan matters to him a lot. Pinky gives an ultimatum to Anika that she should leave, Shivaay and do something so that he himself throws her out otherwise she'll tell him about his illegitimacy.