Absolute nonsense talk by Mrs. Sharma, IMHO. And crappy writing by creatives.
For 6 years, she didn’t move on because SHE was stuck in the past. So actually SHE herself is the third party, but Mrs. Sharma always finds a way to blame others, specifically Abhimanyu.
If she had any attraction, inclination towards AA then who was stopping her from moving on. They were legally married, they were tucked away isolated from the whole family, so had no other interferences. Don’t middle class or poor families have a married life inspite of economic struggles etc. But if she herself wasn’t ready for it then why blame it on “third person”. But all this is beyond Mrs. Sharma’s comprehension, can’t expect much from her or her writers 🤦🏻♀️