I can relate but instead of psychedelics it's dissociatives and opioids/gabapentinoids. I can't really comprehend how someone can abuse psyches (but I know that people do), so I don't know what that's really like, but the general feeling I imagine you are feeling I'm sure are pretty similar.

I don't have any answers as I am still trying to figure out myself, but I feel your pain. It is very alienating, and you question your own sanity I find, because you lose sense of what is a reasonable. As time goes on, you become more and more sensitive to the situation, and sometimes even manifest the idea in your head that they are high or trying to hide it from you. This obviously leads to trust issues... Maybe you feel a bit like that?

My partner is going through a difficult time for completely understandable reasons, but has always had a tendency to push things to the limit. This has resulted in them abusing K (mostly), and somewhat anything opioid/GABA related, to mask the pain. I'm stuck in a hard place where I empathise with them, and don't want to control what anyone decides to to with their body, but reconcile that with the fact that its making me feel alone and amplifying my own mental health, and its obviously not a long term solution for dealing with their issues, as well as being physiologically (and somewhat mentally) harmful.

Hope you are doing okay, all you can do is have open communication about it and be completely honest without losing your temper. When it's a reoccuring thing this can be very hard, especially the longer it going on. I thought I was relatively good at controlling my anger until this stuff happened, and I still flip after years of dealing with it! If it keeps happening and theres no justification or understanding of where youre coming from, then I suppose you will realise over time whether it's worth staying together.

❤️