They didn't kept secret
It was more like they didn't get a chance to tell her conversation us point pe Gaye kaha
Conversation ghum phir ke betrayal pe arahi thi
Nahi yrr..
They could have told clearly...but viru was more like..it would hurt sakshi more...viru told everything..till the part jaha tak he never started caring for her..
He skipped all after that..he was more like..sakshi tu purvi ki haalat samj..and then sakshi dialogue which was apt ki she cant share husband..neither any woman will...viru was still in dilemna..who to hurt..
So he was much more hurt than anyone
Purvi said..she was just a molkki..she never mentioned now they both like each other