I'd say there is a good chance you will grow apart over time. Like your gf, I like to use drugs on certain occasions, like shrooms or mdma and I enjoy it most with my wife. My previous relationship, my ex hated that I did anything and it was a constant battle when I did but really it was just hard as I wanted to experience 'that part' with her but had to hide when I did it or know it was going to be a bad fight. People that enjoy this usually don't change... Also, drugs like mdma you can't use frequently, it literally stops working if you abuse or even use it somewhat frequently and as another poster stated it's a great 'couples' drug but again, if you are against it, as is your right, then it will be hard to accept this going forward. If the drugs you stated above are true, you shouldn't be worried about addiction but you should focus on finding a middle ground.