I want a master bedroom in my home!

Hi, I’m a 34 year old woman and married in a family, My husband is a businessman. I have one daughter and my mother in law lives with us. My husband has an elder brother and he is a govt. officer. He was posted outside our city and after 5 years he is coming back to our city. So my mother in law cried and said to my husband that she want a complete family. So requested my husband if they can stay in this house as this is big enough flat. It is 3 BHK. We live in a master bedroom, and my mother in law lives in second room. Other one is a guest room. Now my husband has asked me to empty the master bedroom that is bigger with attached washroom and asking me to shift to guest room. I didn’t like this and because of this we had a big fight. My husband think am not a good woman and similarly my mother in law also started hating me for that. Why would we shift to a different room, why cant they move to the guest room, because of my inlaws behaviour, iam feeling very guilty of being like this. Kindly suggest if am thinking anything wrong.