Not like I expected to stick with this one after seeing the key art, but it took me 3 minutes to drop this.
Saying that your boss gave you an ulcer is stupid (and not medical). Yes, stress can be a contributing factor to ulcers, but it's not like that alone results in one. Unless you are in constant stress, which means that you need to find ways to solve that, and just changing a job would not be enough. Having ulcer issues and not having a medicine on hand - is doubly stupid.
Assuming your new boss is an abuser even before you talked to him is just ridiculous. Again, I get it, stress from previous one, trust issues, whatnot, but... Be cautious, yes, but do not blindly assume, because that will only feed your stress. And since you are assuming that, it means that you have not really sorted anything out yet, which proves my point.
But either way, I am not the target demographic here. This is probably aimed at people who write BL fanfics. It will probably be feeding you with lots of small interactions like "he's cute! oh, wait, I'm not really gay! but he's cute!', and then mangakas will draw hentai books, that will turn those moments into "I realized I am gay" stories. Nothing wrong with that, just not my thing.