So my SO wants to move in with his sister since she needs help on rent and we cant afford our…

So my SO wants to move in with his sister since she needs help on rent and we cant afford our apartment anymore. she has a two bedroom and she is never there cause she is at her boyfriends but she also has a son who stay with his grandparents most of the time. My SO has it where we are going to sleep in the living room and our son will share a room with his nephew but i dont wanna be in the living room i want my own room with my man and my son. Her son comes over maybe once a week and she is home maybe once a week and we are paying $600 a month so i really think we should have one of the rooms. my sons the most important so as long as he has a room thats fine but im just really uncomfortable with staying in the living room and then on top of that we have a cat who has a hard time adjusting to a new environment and im worried his nephew is going to get rough with my cat and my cat might scratch him and if we had our own room i could keep him in the room when he is there. just doesnt seem fair to me