Does a certificate of occupancy allow you to rent a "rec room" / "storage room" into a rental dwelling?

I rent a 3bed backhouse in an R-1 zoning neighborhood with mother and brother. Recently my gf moved in with me and now landlord wants to kick us out or raise our rent. I apologized for not letting him know ahead of time about her moving in. I offered to pay $50 extra since it was only going to be temporary, at least till she found a job. He declined and wanted $200 plus $200 for last month shes been living there. I felt it was unfair since we don't have a/c unit and heater barely works and nobody is hardly ever home. He also kept asking me on numerous occassions if she was my gf or my wife, and told my mother I couldn't have my son over (shared custody). I feel harassed and discriminated. I'm hesitant to file a complaint because I don't know if that CofO allows him to rent. Options??