Cimba, I finished watching the epi just now. Yes, DM is being unfair to Santu. He might not want to except anyone else other then SHU as his wife, but, the fact remains that Santu is a part of his family now and IS HIS WIFE. YES, he claims to me a fair and a just man, but, he is human after all and as such, not above human flaws. He might be fair and just to everyone around him, but, as far as his own personal life goes, he is being damn stubborn and unrelenting. He has given Santu a fair treatment with everything else other then from himself. I know he will learn in time, regret his treatment with Santu and ask for her forgiveness. DM is a good man, but, as any other human, he has flaws as well - it makes him more real. The flaws in him makes him all the more interesting for me as a viewer.
PS: I was hurt as well when he said that to Pinakin about Santu, but, then, I thought to myself, tera bhi din aayega bacchu, when you will regret these unfairness and I for one will be waiting with relish to watch that scene. GOSH! I can't imagine just how mindblowing he will, be when he starts realising Santu's place in his life, starts understanding and starts accepting her.