I'm Confused

I don't know which behaviors  to attribute to ADHD and which are "just the way he is". I have been with my boyfriend for a little over a year,  In the spring, he lied to me about smoking pot, and apologized for not being honest with me.  I explained that lying hurt me, that I felt as if I weren't worthy of the truth. 

Fast forward to two weeks ago.  The signs were there.  I know when something is off between us.  I came over to his place, and there was an apology card/note, along with some flowers.

He admitted smoking again.  Ha had been under alot of stress lately, and smoking calms him down.  He said : I need to find a way to tell you, but I don't know how.  I don't want to hurt you".

This morning, I found a vial on the coffee table, when I was cleaning.  It looked like a tube from an eyeglass repair kit.  On the tube was a sticker that said The Clear Blue Raz.  I didn't know what it was so I Googled it.

Technically, he isn't smoking pot.  He is dabbing, a term my sister used.  I didn't know what it was.  She says it can be dangerous, because it contains a heavy dose of THC.  She said the percentage back when she used to use it was around 5-10% THC.  Now, its upward of 90%.  She said that people have had seizures, and passed out from using it.  Even when purchasing it from a dispensary.

I am worried about him.  I am upset about his lying but I don't know what to do.  I've spent hours crying and upset.