I think your bf needs to deal with his issues on his own.
And I think you need to deal with your issues on your own.
Please get educated about addiction, there is a ton of stuff to read here on the forum.
Yours is the typical addict co dependent relationship, as you said , he takes you give.
Al anon would be a great resource for you and individual counseling as well.
You are young, there is so much more to life then being used by a drug addict.
If you look in the substance abuse forum there are several threads there about pot addiction.
I hope you stick around, there is a lot of wisdom here, it sounds like you could use a lot of support and help.
You do not have to live this way, you are being used. It is probably in your best interest to go no contact with this guy and begin to take control of your own life.
We are here and we care. Hugs Katie