When she married Rishabh 4 the 1st time,she didn't make a trouble!She saved Anu from a trouble.
When she married Anu,she loved him,n her children,Vis,Tuski told her to do so!Had she no right to live happily after her husband's death!So she didn't make any trouble to any1!Rishabh married her in a wrong way!So he too had to pay 4 this!And that's why only he was sorry/unhappy in that track!
When she married Rishabh 2nd time,she loved him helluva!None had/has problem or trouble 4 this!Coz every1 knew that Prerna was/is/will be of only Rishabh after the 8 yrs!
So nothing trouble she made!And truth is she can never satisfy Rishabh n Anurag both at the same time coz both of them love her n want to be with her!So Prerna has nothing to do with it!