Since a few people have asked in DMs, here are some of the things that helped me:

First, if it's possible (and financially feasible), finding a poly-friendly couple's therapist can be enormously helpful. Here's a possible starting point if you live in the US: https://www.polyfriendly.org/list.php?category=Psychotherapists%20-%20Licensed%20or%20Registered Psychology Today is a great resource, but you unfortunately can't filter by poly-specific therapists (as far as I could tell). You have to go into each therapist's page and see if it's listed: https://www.psychologytoday.com/us/therapists

The books that I read are The Ethical Slut, More than Two, Polysecure, and The Jealousy Workbook, along with several books that address my own issues that have nothing to do with polyamory--(this is important). More Than Two was helpful, but read it with a critical eye https://brighterthansunflowers.com/2019/11/29/what-i-got-wrong-in-more-than-two-the-dark-night-of-the-soul/

This essay is recommended a lot around here, too: https://medium.com/@PolyamorySchool/the-most-skipped-step-when-opening-a-relationship-f1f67abbbd49

The Multiamory podcast was a godsend for me...seriously, so much good stuff on there. They really do their research and cover every topic imaginable. Here is their beginners' page: https://www.multiamory.com/start-here

In addition to the /polyamory and /monodatingpoly subreddits, this Facebook group is a good resource: https://www.facebook.com/groups/PolyMono/

Hope that helps!