1) Arnav and Khushi have a kid. They are separated. I think everyone believe Khushi is dead. Anjali meets Khushi who say her name is Muskaan and hires her as babysiter. Arnav gets jealous when Muskaan friends come to stay in RM. He tries to make her jealous with help of la. Later he finds out she have some medical condition.
2) Khushi returns to RM with Arnav's cousin(or someone Arnav know). Arnav thinks she got married because she changed her surname and she also have miscarriage. Arnav taunts her saying she is cheating on her husband with his cousin. Later he throws her ring out of the car. Payal tells him that the guy he thought she was married to was like her brother and he realize it was his baby that Khushi lost.