Hi kingskid,
This is sad, I’m afraid I hear this more than I like and your story is identical in every way.
Firstly, your not an expert or a professional addiction advisor so don’t feel guilty if you can’t help.
Your role in the relationship is to be strong and supportive the best you can but if your partners has not admitted to his addiction then you will be in this for as long as he can sustain the lifestyle or you leave the relationship. Only way you can help is to give him an ultimatum in the nicest way. GET help! Help is available and he can do it but he must want to do it and admit his addiction.
You sound like a nice caring person and you obviously want the best for him but remember that your not an expert advisor and your desire to live a healthier more fruitful life needs to be your priority.help him but DON’T become his enabler or long term addiction partner, trust me it’s a horrible path. Enjoy your life.