Well I was still thinking abt Rishabh and then I also realised some other points.
Firstly, we have been saying "How come he trusts komolika, he is too intelligent to trust her" etc. But it's not just him who is trusting komolika..also prerna- who is supposedly very intelligent, is blindly trusting komolika. and prem..he is supposed to be 'more intelligent' than tushar- he used to live with komolika for 5 yrs and was her sidekick..still he too is trusting komolika blindlly. and ofcourse anurag who knows komolika most intimately(she ws his wife, he had made her pregnant)- is also trusting komolika and behaving as if she is his girlfriend or smthing! but since anurahg is not that intelligent,we can ignore that. but d point is- not only rish, but even prerna and prem ,sneha,tushar -all ppl with sm level of intelligence are trusting komolika now.
and second point about turning negative- well i guess when the person closest to u..the person u love, trust, respect d most..betrays u, it can drive u to the brink and u may lose faith in everything- including ur values and principles. this can happen..when u love someone beyond all limits, when u put that one person on a pedestal..and then that very person stabs u in the back, it can change ur personality completely. rish didnt turn negative when prem betrayed him, or when tushar betrayed him. he didnt turn negative when he thought prerna loves anu- both times- 8 yr leap and before 5 yr leap..but he cudnt accept that prerna wud go to the extent of planning his murder just to be with anurag. And for Rishabh, prerna was everything. She was d one who changed his life completely..who loved him and made him fall in love with her. She made him BELIEVE in love. he changed a lot and became more n more positive because of her. and when his basic beliefs were shattered, he felt that the world was meaningless. hence, it drove him towards doing all wrong things.
I am not really justifying that any1 turning negative is right, but rish turning negative is due to all these reasons..so yeah..i can understand him. and I am not against him, though I am against some of his actions .