cheesecake,
You're definitely being the logical and protective one.
Drugs are not a "joint expense" in my humble opinion. If he wants to buy them, let him find the money to do so. He might even need to get a job.
And the anger and manipulation is pretty typical. Try to hang in there, and drop on in here any time you need a shoulder, some advice, a hug, or a good laugh.
WE know how hard you're trying.
Love,
GL