Sorry for the long story but anyone please help!!!!

I feel like I have no where to turn.. In 2010 I moved to a new town & met this guy who was my only friend there (I'm a country girl who moved to the city. I didn't fit in) but he saw who I was deep down and liked me for it. We were so close he was helping me through my anorexia & bulimia. We started dating and things were going perfectly. By 2011 I now weighed 36kg and was the healthiest I'd been in years. Everything just seemed so perfect it was like we were meant to be together. 2012 came around and things started going badly between us, he always seemed mad at me and was constantly blaming me for any thing he could. He became very erratic emotionally and was completely unreasonable to talk to. I then found out I was pregnant, because of our past I thought we were just going through a rough patch so I was excited to have a baby with him. Only 2 weeks after I told him I was pregnant he was fired from his job for arguing & using his phone while working & I was so scared. I didn't know how we could support our child. Every day I'd help him apply for jobs, I even updated his resume for him. But he didn't seem interested. I ended up getting myself a job, saving for the baby & supporting us both because he wouldn't. He was never thankful for what I was doing, he was just becoming more & more erratic. Almost like he had bi-polar. He would tell me he was going out for an hour & come home 7 hours later… It went on for months & I tried to put it past me for the baby. I thought he was just trying to spend as much time with his friends as possible before becoming a father. Yet the day came that I was in labor. I woke up at 4am in minor labor pains (which I didn't recognize at the time as labor) and had a bath then went back to sleep. I was awoken at 8am in terrible labor pains & to no surprise, he had gone out. I called and called him yet got no answer until 11am. I told him I was in labor & needed to go to the hospital (he was my only way there) and he eventually came home at 2pm & took me to the hospital. He wouldn't tell me where he had been or anything. A few months passed after our daughter was born, and he was a terrible father. Still no job yet gone all day every day. He'd come back late at night and go to sleep so I still had to do everything by myself. Eventually he's friend told me he was a heroin addict. I didn't want to believe it, but it all made sense. I was heart broken & confronted him. He admitted it to me & I was an emotional wreck. A few weeks passed & I told him I'd get back with him if he got clean. Every day I'd go with him to get methadone & to his doctor visits but he would always end up using again. I kept trying and trying to get him clean. I loved him so much I wanted to help him. But he never wanted to help himself. He started stealing from me & selling most of the things in our house. Every day he'd tell me he'd kill himself because he needed a hot, one day he even covered himself in petrol & lighting himself on fire (luckily no serious injuries) He became violent & stole my car because I wouldn't lend him money. I ended up calling the police because I was holding my baby when it happened, I was scared for her life. He got told to go to rehab or jail, so off to rehab he went. I was so happy he was out of my life. But it was so hard. When he came out of rehab I stupidly took him back, seeing him as the person I first fell in love with was incredible. I had missed him so much, when he was an addict it was like his body was here but his mind wasn't. A few months later & he started to get a bit moody again. Months pass and it just got worse. I thought nothing of it, until he stole from me again & started arguing with everyone he spoke to. I went through his phone & found out he was back on heroin. I can't even look at him now, but I love him. I love who he is, not who the drug makes him. We've been through so much together I don't know what to do?