So I went to his store he owns to talk to him. Turns out earlier, because I had said I was most likely not going to be home when he got there - he made plans to hang out with his friend Mike.
I'm starting to wonder why I missed work today, why I was stressed all day, why I threatened to leave again and he got to have a nice day at work and even made plans with his friend - despite what I was going through. I carry the brunt and the weight of his problems, it seems, so he doesn't have to. Because who cares that I wasn't going to be there when he got home, Mike is an equally acceptable replacement.
I asked "How can you say in all honesty that you want me in your life and then, when I say I won't be there when you get home, get over it quick enough to make plans with a friend?" - never did get an answer to that question.
I'm reaching the end of my rope...