I read Prerna's Mangalsutra breaks due to Cookie and I have a theory. Here it goes -
The mangalsutra might break, AB may know the truth behind why Prerna got married to RB..RB might decide to set Prerna free.... And the pregnancy news will be out separating and distancing AB and Prerna forever.. Because according to me the pregnancy news is kept hidden until now, only for it to be the trump card in driving a final wedge between the EX lovers..
Right now I think the stage is being set not for Prerna and AB's reunion, but to tear them apart.. And then Rishabh will unleash his wrath..And Prerna might even stop caring..
Since the mangalsutra is breaking because of Cookie, the symbolism may work like this, Rishabh married Prerna for Cookie's sake, now because of Cookie the mangalsutra breaks and this might as well mean that this time when Prerna and AB's rishta breaks because of the pregnancy news, Prerna will break her ties with the past and woh khud apni marzi se agge aake Rishabh ka haath thaamegi.. And in the past RB and Prerna came together because of Cookie, this time they will come together based on the mutual respect and mutual trust for one another - My Take!!