HN is not /r/relationships so I don't want to discuss healthy relationships too much, but their partner not seeing sitting at a computer as working does not mean that reminding them that it is in fact working won't change their behavior.

If anything I empathize with OP because I had the exact same issue with my partner where she'd come to show me tiktoks while I was working but when I said I did not want to be disturbed she stopped. Sure she teased me about being too serious but I just don't see how a healthy relationship could have something like this escalate...