3 room apartment in Gothenburg

I want to rent out the lower floor of my duplex apartment with a view of Ullevi. I am usually at my partner's apartment, but I do not intend to move in with her permanently. We enjoy living apart. I live upstairs. I have my own toilet on the second floor. I have built a wooden cube with a lid and insulation for the upper floor to provide privacy, as we had teenage children up there before. I also prepare meals up there. I have no access to the lower floor except for passing through to enter and exit. I have seen that someone with a similar s...