Drug addict husband

I have had suspicions for months now. I never confronted him because I wanted to believe him. But here we are.....

just a few hours ago I confronted my husband about his drug use. He told me that he could not lie anymore, and yes he has been using for 6 months. This is a relapse for him. 3 years ago (plus some) he entered a methadone clinic for addiction treatment. When the news came that I was pregnant he began to scale down his treatment, and work his way toward sobriety. He did good for 2.5 years. But he just admitted he has been using. We have been struggling financially for a while. I had gone part time to cut back on childcare costs: but when the ends weren’t meeting I went back to full time. And then the ends still weren’t meeting. Tonight I knew the truth. I was preparing to leave. We talked and he spilled the beans about how he was using again and thought he would be able to find help before I figured things out. In June he had withdraw symptoms and I asked him about it. He said it must be a flu and not to worry about it. I didn’t for a while. I love him and didn’t want to assume the worst just because of our past. But I was right then, and I know I’m right now. He offered a divorce and to move out which meant living in his car (in my name and I’m responsible for payment and insurance). I told him he could stay, but we could not be together. I need help with my son, and he said he would seek treatment. I told him how he broke my trust, and how he deserves to be thrown out. He said he would deserve that, and continued to offer him leaving. He tells me I deserve better, and I told him to be better. He said he deserved whatever I gave him. I explained how he ruined our family financially, and broke my trust. I sold him how confused our dog was on Saturday as we euthanized him. Because my husband left the room to go pay his drug dealer in the parking lot after they gave the dog the sedative but not the injection to put him to sleep. Because of that comment, I am a heartless bitch. Apparently I cut deep with that, but he doesn’t feel a great deal of remorse about all the credit card debt we have accumulated Because of his habit. I just don’t know what else to do. I know addiction is not a choice, but we went through this before. I don’t have sympathy this time because apparently his son means everything to him, and he was still ok with fueling his addiction while I scrounged change for food for our child. He’s sleeping on our couch and not in the streets, with a promise to find an addiction doctor tomorrow. Would I be wrong to leave if he is not able to find treatment? This would mean confessing everything to my dad and moving our son and myself into a single room until I could sell our house and find an apartment or something cheap. I feel like an asshole, but I don’t know that I can repeat this process again.