I watched all of Kausauti Zindagi number 1. So obviously they are not following the script to the T.
In the original Anurag married Komolika and she was pregnant and she aborted the baby. On the other side Prerna gave birth to Prem which they passed off as her brother and sister in law's baby in the beginning. Her sister was never pregnant. After Anurag and Komolika's marriage fell apart Prerna and Anurag were supposed to get married but Basu publications went bankrupt and then the entry of Bajaj and he blackmailed Prerna to marry him and he would save Basu publications. So Prerna married him and he had 3 children. The little girl was blind and her name was Cookie and then he had a teenage son and daughter who hated Prerna at first but later on they liked her.
In came Bajaj's first wife and he somehow became crippled so Prerna thought he was dead and she married Anurag but this is when all the misunderstandings came up. She kept running to Bajaj when she was with Anurag and then she was pregnant and Anurag thought that it was Bajaj's kid and after Prem died Prerna left Anurag and gave birth the Sneha. Then she married Bajaj but then Sneha had cancer and in order to save her she had to have a child with Anurag hence Prem 2 was born. Prerna after giving birth was dying to be with Bajaj which Anurag made happen. Then Prem 2 was kidnapped by Komolika and hence leap after leap.
But at the end Bajaj was in a metal asylum and Komolika killed Anurag and Prerna and their souls left together in the black suit and long red dupatta.
But I could never understand that Prerna loved Bajaj but always called him Mr.Bajaj. Prerna through the whole 8 years this drama was on was always jumping back and forth between Mr.Bajaj and Anuraj