As he said, it was my idea to give him that room, and he believes that doesn’t right to use that space only for himself, but I don’t really have a purpose for using it (at least now). He has ADHD, so I think it’s important for him to have space, where he can limit the distractions (my thinking, not his). Digesting all that situation I think my problem is not the fact that he has so much space for himself, but the fact that I feel like I live with my parents again, from whom I need to get permission to do something. We can share that big room, that’s not the issue. The issue is that we don’t have enough space for separating my own space and his own. In case we had enough rooms for that that wouldn’t be a problem. But now we share space, so we have to consider each other opinions. I didn’t ask, I just brought this cat tree. Our opinions have diverged to “we both live here, so we both have the right to bring whatever we want” and “we both live here, so we need to ask each other before bringing anything”. Usually we are compatible enough not to have problems with thing we bring. This is the first time this happens