Dating an Addict - How do I help?

My boyfriend (30m) has been using a variety of drugs since his early teens, and has been to AA/NA & rehab before we started dating a year and a half ago. His primary drug of choice is coke & alcohol, and his come downs are awful. His mood swings are all over the place, and when he gets angry it’s explosive. He’s definitely paranoid. His energy when he’s not using is pretty much non-existent. He’ll go days without showering bc he’s so tired, and can’t be counted on for any apartment responsibilities. He just “doesn’t care” about almost anything. If he’s not working he has no motivation for anything except partying.

From what I know, and have seen, he uses at least weekly. And when he gets going it’s never a bump or two, it’s a full bottle of whiskey and as much coke as he can handle. When he’s not doing coke he will drink an entire bottle just to fall asleep.

I will partake sometimes but mostly I smoke weed and drink on the weekends. I’ve told him I’d quite everything if that would help. We’ve talked about him taking a break but when it comes down to it, he’s barely slowing down. Much more than when we started dating but it’s still pretty constant. He tries to compare his coke use to my daily marijuana use, and know drug use is drug use, but to me a hit mid workday or before bed is just different from him staying up for 24+ hours and then sleeping for 13 hours to recover. I’m worried about it. I’m worried about what this is doing to his body and his mind. It’s not sustainable.

I just don’t know where to start. He usually throws my weeds use in my face and cuts off the conversation. If anyone has been in his position before what should I stop doing? What would have been helpful?