A door can separate two people who are ready for different amounts of company.

Living alongside somebody means constantly negotiating an invisible quantity. One person has had enough talk by six and the other has been alone all day, and neither state is a comment on the relationship, though both are easily read as one. A closed door is usually about capacity rather than about you. Company is a need with a level, and levels differ.

Say your number aloud instead of performing it: I need an hour, then I would like to sit with you. Ask theirs rather than guessing. Give a closed door the most ordinary explanation available.