I guess all I can say is, I was his age, I drank a lot, I finished a relationship because I felt I was being nagged to settle down. n my head, I was partying, no harm to anyone,I was young and my boyfriend at the time was a killjoy in my view. You wont win against him, he will not view his lifestyle hazardous, as you do. life has much more to offer than for you to be picking up the pieces, and dealing with the sh*tstorm us folk create when we are drinking.
As one woman to another, and also as someone who acted entirely as your partner is now, and ended an engagement so I could drink hassle free. Go, leave and don't look back. One day he may sober up and realise what he lost, but is not anytime soon my friend. Go be happy with someone that is in the same headspace as you, trust all of us on this when we say to leave this relationship be.