This come in my mind-
If we take rishabs and choti Maas age into consideration they had to be somewhere between 10 years from each other. Is that possible that ragini was a family member of choti maa, maybe a door ki rishtedar or a friend. Maybe she was the one who destroyed rishab ragini relationship and that's why rishab keeps threatening her that if ragini truth comes out they both will be in trouble. Also yesterday epi she said geetu has to pay a price for being a daughter of this family, maybe during ragini she sacrificed something important too that's why the grudge for this family, rishab and geetu. She wants both to go down that's why she don't care geetu is getting mentally tortured, at the same time leaves no stone untouched to destroy rishabs character like Chanda pregnancy. Also she was the one who paid chandas hubby to kill G, for now looks like she's another villain trying to destroy sibiling duo side by side abhimanyu