Hi, i am sorry you are going through this! I have a similar situation with my now ex partner using cocaine, not the debt however as bills were always paid but he never has any money once bills are paid due to buying lots of cocaine.
I am going through lawyers about selling our home and contact with kids. I have stopped contact but he wants to see them. I have requested he seeks help through a drug rehabilitation programme and seeks counselling for his anger and depression, whether he does this or not is a different story but i have also asked for drug testing by hair follicle. I was advised that many men try to shave their hair before testing or dye it. I am just informing you about this, there is also certain detox shampoos that t they may use to try cheat the test, look it up online.
Big hugs to you xx