Future baby daddy, and the well being of unborn child..

My current significant other and I haven't been on the best of terms. I'm not sure what exactly to do with him, because there is HOPE that he will change by the grace of God, but at the same time, I'm taking into account all his behavior and noticing a consistant pattern. He adores me, or so he makes clear with his words. However the drugs keep him away, needless to say that when he's home he's easily aggravated. He almost always repents for his actions, but makes sure to let me know that the FAULT is mine when he puts his hands on me. "I'm not acting like his woman," or I'm talking to somebody that I shouldn't be. " YOU get hurt. when I GET HURT." He'll go through one night of complete chaos, an anger fit that scares the **** out of me. Then for a couple weeks he'll be back to sweet loving boyfriend, who's excited for baby to come. Then something will happen again to set him off. He swears to God he's going to change, he quit doing drugs...then he does them again... I hate it, it's killing me... I'm only 3 months along, and right now it's DIFFICULT to picture doing this on my own....i just, need advice...