I just wanted to update this discussion. It turns out that my husband's path isn't unusual at all. He's using again. He was getting nasty and negative again, along with falling asleep while sitting up on the couch. I thought his pupils looked small and asked him to take a test. He refused and told me he'd "found" some pills in a cabinet.
I'm trying to focus on me and getting the best outcome for my life. I've told him that I won't be with him while he's using, and that his proving he's clean and going to counseling together is the only path forward I see. He told me that he likes taking drugs and wants to be accepted for who he is.
I'm going to make an appointment to see the counselor he and I saw together once (after which he neglected to do any of the homework she gave us.) I want him to go with me, but I can't control his behavior.
This sucks, and I'm stuck home completely alone, while he works every day in an essential business. He's at a hotel for now.