AIBU about my partner still attending raves/using drugs?

[SnowdropsEtc]

So my DP and I have been together for almost a year.
In most other aspects this relationship is the best, most healthy, reciprocal, caring and communicative relationship I've ever had. He really is a genuine and lovely person, holds down a good job and has a lovely and strongly bonded family. Consistently he is kind, shows up for our relationship, and has intentions for the future together.

Lately it is getting into spring (we are over in New Zealand at the moment) and the locals throw "bush doofs" (think warehouse raves, but in the forest)... And he has been attending them.
This one he went to over the weekend, he admits he was quite drunk and also took illegal substances (he spoke of MDMA, but there could have been more...there were plenty of others around).

I was out hiking in the mountains and have been quite thrown and very off-put by hearing this.

I've been bothered from the start by the fact that he drinks (a leftover from an alcohol father's imprint on my life) and have been making peace with it... Because well, most people drink!

Problem is, he is the first to admit that he feels it's a problem. He explains it that he feels he doesn't have control over how much he drinks once he starts...one drink and he will continue to drink. He has tried to become sober several times and only ever managed almost a month.

He has also had far more and regular involvement with parties and recreational drugs in the past, but seemed to have been leaving them behind.
I'm just concerned for the future, because I don't want to date a party animal. Been there done that. It was shit and I felt like I was mumming a toddler when he was off his face.
Don't want to go there again!

Like I said, in all other ways, he is wonderful. My friends all think so too and hope we stay together.
It's rather confusing and I don't know whether I'm being rational or unfair.

TLDR: DP attended rave on the weekend with recreational substance abuse. This is triggering for me and brought up a lot of doubts.
AIBU?

Occasional MDMA use wouldn't bother me. Steer clear of cokeheads though.

we are by default always less mature than our female counterparts

That's really not true. I know many thoughtful, capable men who are more emotionally and psychologically mature than some of their female counterparts. Saying "oh we're just less mature by default" is such a cop out.

I stand corrected, i used a very sweeping generalisation, you are correct, some men will be mature. Just correcting my stance on that.

Men aren’t fixer uppers and they aren’t works in progress. What you’re seeing is the finished product. Given you can’t change him you have two choices - accept it or end it. If you are here to ask how to get him to stop the short answer is that you can’t - not really, not long term, because that’s not who he is.

Him having a high tolerance for alcohol is not actually good news.

It means his body is habituated to it, which is a step on the road to alcoholism. And while at 29, his body can cope and he can function, as he gets older, things will start to fail/deteriorate.

Problem is, he is the first to admit that he feels it's a problem. He explains it that he feels he doesn't have control over how much he drinks once he starts...one drink and he will continue to drink. He has tried to become sober several times and only ever managed almost a month.

This is really worrying.

Personally, I'd cut your losses rather than spending years of your life on a punt that he will sort himself out.