I'm not sure if Morgan Brice's Burn counts as a book or not, since it clocks in at 100 pages and is listed as volume 1.5 on Goodreads. However, I own a copy and I finished it, so it's getting treated as one. (I know, technically, it's a novella, but....)
One of the original reviews of Brokeback Mountain I read summed it up as "90 minutes of angst, 1 minute of pleasure", neglecting to mention the 1 minute of pleasure happens roughly 15 minutes in. Burn is a bit like that, since we're picking up in the months following the events of Witchbane, as Seth and Evan try to find relationship balances in a fairly new romance that involves moving in together in Seth's RV. That Seth is trying to train Evan in the fine art of monster hunting and rote magicks doesn't help with this.
So, we follow Seth and Evan from Richmond to Centralia, through battles with a vengeful ghost, ghouls, zombies, and kobalds and a bunch of relationship drama and jealousies as Seth goes through the existential angst of how someone he loves would be better off with someone else and Evan thinks Seth isn't giving him enough credit for the things he can bring to the table.
This leads to both parties doing stupid things, and finally coming to terms in the end, along with a few shout outs to characters from other series, written under both Morgan Brice and Gail Z. Martin.
Honestly, I kind of liked this better than the first one, since it shows a less idealized version of boy meets boy, where boy and boy figure out sex only gets you so far when the rent's due, there's no food in the house, and someone ate the last Twinkie.