Drug testing is generally something done by institutions, employers or parents.
Drug testing your partner and him crying in front of you for failing the test shows a serious lack of trust, respect as well as a power imbalance in the relationship.
I would never think of drug testing someone I respect and I see as an equal and these days, I would not be in a relationship with someone I don't trust and respect.
Is this the kind of relationship you want to be in?
What are you doing for you?