Acc to the spoiler Why Paridhi is sad when she see arti and yash talk together with love.
I think both pratik and paridi hide the truth about that paridhi can't became a mother. So she try to shower her love to aayu but when she heared the conversation of arya related to aayu then she realised arya are their parents.
Or
When paridhi hearted the conversation of arya related to aayu and kids and how they kids play a important role in their parents to come more near to each other and fill their life full of happiness. Then she realised it that now she can be try to became a mother and give birth to a baby who make her and pratik bonding too strong.
Acc to me , second option is much better than first one acc to spoiler. What u say guys? She can't jealous with arya but when she see them together,she want such bonding with pratik also.