@Chithra, I don't think Niranjan is a psychopath because he has not been shown one.
He is actually a very insecure egoistic person. He subdues Anjali - the one on whom he relies the most because that is the only way he can feel superior. Anjali is more intelligent than him and on top of that she has emotions just like Shlok does. There has been no backstory of Anjali and Niranjan so far. And I highly doubt that they would do justice to it either based on what they have shown of Swati and Shlok and how they have transformed Shlok.
His and Anjali's is a very complicated relationship. This is based on what has been shown so far. It seems that Anjali was from a progressive background and probably was of a middle class family. She was too a free spirit - past photos of loose hair and lots of pictures with her kids etc. (from the collage that Astha made of her). Niranjan is a smart man who is self made. He is corrupt but also very resourceful. He was definitely from a conservative background but it did not imply that his family treated women like dirt. It had seemed as if Niranjan used all the traditions to subdue Anjali whom he wants to possess. He knows that deep down Anjali has moved away from him. She does not accept his gifts and locks them in the trunk. She never smiles and gives mechanical answer. The more she is emotionally distant from him, the more he tries to subdue her by force. His constant asking about whether he is right is a sign of insecurity. He killed Anjali's spirit in his obsession for possessing her. He did the same with Shlok who got so immersed in his darkness. He loves Shlok the most (in his creepy possessive way) because Shlok is the one who is like Anjali - sensitive, independent, emotional and smart. Anjali is the one who figured out that Astha coming to the house would shake its foundation. Niranjan did not listen to her in his ego.
So I don't think Niranjan enjoys torture, where he would like his daughter to be tortured. Previously, it was shown from the beginning that though Niranjan is brutal with Anjali, he does not want the same fate for Jyoti. He had been been furious with Abhay in the past when he had realized that Abhay in his greed had taken every piece of jewelry from Jyoti. He had also liked that Abhay had gone for the gender test. So I don't think he wants to send Jyoti so that he can enjoy her torture at Abhay's hands. He wants her to be gone because Jyoti is of no value to him. Even the people who discriminate between boys and girls invite their girls for important function because that is expected in the society.
He definitely does not like Abhay. He used him in the beginning (by giving him the greed of getting the old home) because he wanted Shlok to go after Astha. And that's what happened. As soon as Shlok decided to give back the old house (though it remained in Anjali's name), he just removed Abhay from the project.
He would not have been able to control a SIL if he was from a prestigious family an dhad money of his own. That's why Jyoti was married to him and that's why Sojal has been brought to this house. He might not respect Varad, but he uses Varad all the time whenever he needs help with the media.
But whatever Niranjan is, his weakness is Shlok. He desperately seeks approval of Shlok and for that reason, he shows the image to Shlok . That image is actually how real Anjali is. So he knows that Shlok actually loves Anjali and not him. All these aspects of Niranjan have disappeared now. They are making him more and more like Abhay and all his shrewdness and manipulation is going away.
The only thing I can say is that CVs have become obsessed with Maryada, and trying to mold Niranjan into the villain from that show. Just as Shlok is not some soft romantic guy, Niranjan is also not just a wife beater. He is more complex than that.
Today they showed Abhay manipulating Niranjan and not the other way around. That did not make sense. Suddenly Abhay is made smart and for that they brought down both Niranjan and Shlok.
Shlok might lose control in certain circumstances, but he has not been shown to do that in case of Jyoti. Today he was totally brainless where Jyoti was concerned. So in order to make Abhay and Astha smart, they ended up diluting Anjali, Shlok and Niranjan.