That sucks Charlie man. Although I haven't had the exact same experience I have for sure had some almost-serious relationships end prematurely for substance-(ab)use related reasons. In retrospect the ones where it wasn't a conscious decision choosing substance use over trying to make it work, I probably did unconsciously sabotage them (not saying this is what you did, just was - probably - what I did). I try not to regret things and I guess I don't really because they were all necessary experiences that made me who I am today, but, today I think if someone important to me had an explicitly stated problem with my substance use I would not take such a hardline stance that I absolutely will not quit using substances. Rather, I'd try staying sober for a while and see where it went.
I'm just kinda musing about my own life now moreso so I hope you don't read this as judgey in any way, I think the freedom to use drugs of one's choosing is very close to being a human right of a sort and I hope I manage to express that whenever I get the chance on this forum. But, that said, speaking from the perspective of getting myself into a pretty bad place from some probably fairly tame middle class addictions recently, almost abandoning a bunch of objectively good shit in my life in favour of just being able to use whatever drug I wanted whenever I wanted to, and finally deciding to be sober for a while, even trying out some NA type stuff for a few weeks, more out of respect for a friend who I'd admittedly given a really undeserved hard time over the last year or so than any real desire to get involved in it myself... I must say I do feel a lot more level headed right now than I did around 6 weeks ago, and the idea of an extended period of sobriety - even for other people rather than myself - does not seem so unworkable, unfair or strange.
While I do plan to be sober for an extended period I have no intention of being sober forever. I also probably wouldn't even count using a psychedelic on occasion an interruption in sobriety. Myself though I have always used my love for psychedelics as an excuse to draw a whole bunch of other more harmful substances into the umbrella of "acceptable for somewhat frequent use", which definitely got me into some difficulty.
I kinda think now, in most cases if it's not a problem, it's not a problem - but barring the occasional staunchly anti-drug judgement person (of which there are a few for sure), it's possible that if substance use is causing a problem, then it is impacting other people in my life in a way that I'm either not noticing or just choosing to ignore.
While I ultimately couldn't get past "the differences" and have no intention of going back to 12 step oriented groups there are for sure some nuggets of wisdom to be found there, for me the primary ones being oriented around certain forms of irrational thought that can arise with pretty much any habitual behaviour, maladaptive, substance oriented or not, that one is reluctant to give up. I kinda take the perspective now that if I'm using substances to deal with something, then that's a problem, and when I return to the psychedelic dimension it will be from a genuine curiosity and not something I need to do, or something that has any chance of causing conflict or difficulty in my life, or something I'm hoping will inspire me with some kind of divine revelation about how to live. While psychedelics and for sure other substances can impart the latter lessons, I for sure wasn't learning any of them for a very long time, my life was really not improving. For me, I think a reduced frequency of use has some chance of bringing that back, but even if it doesn't, that's not really important, drugs will always be something I enjoy doing, I don't need to justify that, but it's obvious I won't always be able to enjoy them if I don't respect them and myself enough to figure out a way to enjoy my life properly without them.
Again I hope this doesn't come across as judgey in any way, I really don't mean it to be, don't wanna be that guy banging the sobriety drum either, that doesn't suit me I don't think. I guess the truth is I just kinda wanted to share my own recent experience and this was a good opportunity to. I hope someone reading this can get something useful out of this anyway.