AP,
Very interesting and completely unsurprising. I haven't done any research like you but have to tell you that this was something which was discussed in my circle of friends and JW's character did become the butt of so much ridicule for his dumbness.
Forget business tycoons, even a normal man (of course with his brain in place) would have asked for a paternity test even if he remembered what happened that night. Especially if the woman has betrayed you so badly and if you have seen her viciousness and lack of qualm for destroying her sister's life.
The desire for a child cannot be so strong that you are ready to accept a paternity claim unquestioningly for an ONS and that too when it has the capability to wreak havoc in your life. Acceptance of the child after it has been determined to be yours is a totally different thing.
Kudos to Ekta for succeeding in making JW a 'mera bachha' chanting duffer from a smart and shrewd businessman.