I do believe she deserves this. This may sound harsh to many people, but if there's one thing I hate it is infidelity, whether it is done knowingly or unknowingly.
Paridhi crossed all limits by sleeping with the producer, and her being drunk is no excuse. When a person drinks they should know that they are responsible for whatever they do in their drunken state. If they kill someone in their drunken state then they are still punishable by law. Likewise if they commit adultery in their drunken state they are still responsible for it.
Had Paridhi been raped it would have been another story, but from what we know so far she slept with the producer willingly after becoming drunk. She is 100% responsible for her behavior and deserves the guilt she's going through right now. I would not blame Prateik at all if he divorced her after knowing this truth.