I honestly don't think we will have a positive reaction from Tarachand, on knowing that Sanchi not only doesn't want a divorce, but that she is also deeply in love with Indu Singh.
To be fair Tarachand has ample reason to dislike Indu, that duffer had him beaten and disgraced in front of his own child.
I'm assuming that from a man to man pov, that was huge insult and a direct blow to his manly pride. Tarachand has the role of protector in his family, and Indu showed him just how easy it was for anyone to get past his defenses.
So again Indu has a lot of work to do in proving himself in Tarachand's eyes. He's already rose in Veenaji's and Sanchi's esteem, so now he just has to work on Tarachand. A starting point, might be apologizing for all the c*** he put him and his family through.
IMO personally though I think Tarachand might well go slightly negative. I wouldn't be surprised to see him emotionally blackmail either Sanchi or Indu, to stay away from each other. I would love to see Sanchi bring Tarachand around to the thought of her and Indu being together; but I'm afraid this time the princess will find out she hasn't got Daddy Dearest wrapped around her finger as much as she thought.
Also I wonder how he will find out. Will he figure it out himself? Be taunted with the news from Shoba and/or the Tiwarris? Will Sanchi confess herself? Worst case scenario would be catching INSA in an intimate moment...