TL;DR send per episode alerts as per agreed, but include a prominent easy "click here to switch to a monthly episode summary alert" link in the messages, splitting your list into two lists. Now mail without anxiety.
1) 1% unsubscribe-per-mailing rate really isn't bad or unusual.
2) I doubt I would want a per episode email, BUT if I did suscribe to episode alerts, I might also be very surprised if they stopped coming. So you probably have a mixed population of core fans who want per-episode alerts and are surprised they're not getting them ~weekly, and a bigger group of casual interest who want to remember to look at your website to see if it stays interesting in the future, but who's ideal email frequency is more like once monthly.
That's probably ideally two lists, so ideally you need to split them. If you don't split them, I'd keep doing what they signed up for by default.
3) Keep your simple clear call to action on the web, BUT send messages with a not-next-to-unsubscribe slightly prominent "Hey, you signed up for per-episode alerts, click here if you'd like to be moved to a monthly 'episodes this month' alert instead"
That way the call to action on the web is kept simple (you know this call to action works, maybe don't mess with that), but people get used to there being an action between "do nothing and be annoyed" and "nuclear unsubscribe". This /might/ cut your per-episode-alert unsubscribe rate in half.
I would find this to be polite and considerate mailing behavior, and you in turn could feel free to stop worrying about sending your per-episode alerts.... and focus on a clean simple monthly summary message besides.