I dont think Ravish wants Vividha around more for his mother. He wants her around cause Atharva is responding better to her. And the only way to keep her around, is to pretend they are married.
He clearly said that he is freeing her from the marriage bond, but she was ready to leave, so i believe he jokingly said that its an order for her to stay, so thatt she stays back.
Pretending for Suman, is just that pretension. We will need to wait and see how he plans to get it out to Suman. If he doesnt do anything, then it will wrong on his part.
As for wearing the MS and saying that she will fulfill all the responsibilities of the Bahu, it was Vividha who herself did so.
Infact RAvish even spilled the sindoor, which his mother had given with so much love, just to save Vividha from another burden on her head.
I think after the delay of revealing the truth, which Vividha did. And the way Ravish's life is ruined, and his mother is gonna know the truth and be more heart-broken. He deserves a little bit of support from Vividha.
Earlier he was gonna hurt his mother with just one truth, that the woman due to whom, her husband never loved her, is here and Ravish himself bought her here and is even gonna give her her right.
Now there is one more bomb ticking for him. That is telling that same mother. That his wife is actually in love with that said-woman's son.
I think he deserves to decide when to tell his mother, cause a mother's health is always the highest priority for any child. And after going through so much, and still be helpful without any resentment, he deserves that.