Totally agree with you. The reason
Meera-Dev jodi worked is 'cuz they were friends once and despite being disgusted by what Dev did, she actually saw the remorse he went through. She knows he was truly sorry and tried to put things right. She loved him before and after she could forgive him seeing his repentance.
I don't know how another girl, especially a girl like Nandini (who by-the-way is Geet's sister!!!) could see a life with Dev after finding out his truth.
On a similar note, having overheard Dev try to break Nandini's rishta in the precap, I really hope Geet is still not in a comedy mode!! (with his history, Geet should doubt his intentions...and actually have an objection to this rishta as well)!!!