I don't know what to do.. my fiancé and I live in a 2 bedroom apartment with our 8 week old and his…

I don't know what to do.. my fiancé and I live in a 2 bedroom apartment with our 8 week old and his sister. I thought in the beginning living with her would be helpful but it's actually been a terrible stressor for me and when I try to talk to my fiancé about it he ignores me.. literally as if I said nothing... he always puts her first but we're suppose to be starting our own family....