I don't really understand why he did it exactly, but whatever Shiv did today, was, in one way, really good. He could have thrown her out by not supporting her, but instead, he "supported" her in front of everybody. I mean, I know he said that he wanted to be an "adarsh beta and adarsh son" in front of the family, but he could have played the "injured" husband card and also gathered the family's sympathy...so this was very good!
But now, Kaya will tell the truth, and Shiv will be stuck with Gauri😆😆😆