I don't know if he is referencing someone else or quoting a paraphrase from his own work - but it instantly rang intuitively true to me.
[anything done for the first time releases demons...]
I think a big reason that people my age develop forms of mid-life crisis is the lack of "1st timers". Not necessarily because there exist fewer but because family life, mature social circles, and career structures make it quite hard to encounter 1st timers. You have to make an active effort to meet them, whereas in my younger days I would run across them daily or weekly.
Maybe that would constitute a fine New Year's resolution; weekly 1st timers...or maybe just monthly, depending on your degree of Weltschmerz and suburban assimilation.