I'm so sorry, Lost. You are in a terrible crisis right now. And your children are being greatly impacted. If you can do your best to make sure their schedules remain consistent and protect them from witnessing any confrontations you have with your husband, please try your best to put them first, in spite of the breakdown happening in your marriage and within you. If you have the means, consider having them see a counselor for a while. They are innocent and vulnerable and will need you to put their welfare above all else.
Addiction makes all addicts selfish, but for coldness and cruelty, I think cocaine and all forms of speed are absolutely worst for turning human beings to ice. It is shocking and sickening to witness, and chilling to be in the presence of someone who is high on cocaine. I have a friend whose son is a coke addict. She allows him to live at home (he is 36 years old). I have a few times been in his presence when it was clear he was high and I felt almost light-headed with anxiety and slightly nauseous. I cannot imagine living with anyone who is a coke addict.
Others will share their stories with you, hopefully.
Please put the emotional and physical safety of your children first. And seek outside help for yourself. A visit to a family doctor would be a good first step.