When you husband threatens suicide, you should call the police. He may just be using this to make you feel bad, but it is not worth the risk. If I were you I would get my finances separated from his and start playing hard ball. You did not ask for this situation and if he is on drugs there is nothing you can do to help him. He needs professional help. While you can not force him to become clean, You CAN do everything in your power to make it difficult for him to do drugs. Call his doctors to voice your fears, keep the money away from him. Last but not least insist he gets treatment for his issues. The hardest thing to face is not being able to help someone you love. However, you can not love someone off of drugs.
I wish you the best of luck. And please protect your children from seeing things they should not. Contact an Alanon Club in your area as they can give you much better information on how to take care of yourself and your family.
Fondly, Leah