Yeah, I'm with Cormacaroni and the rest of the common-sense speakers here: you can't help her if she doesn't want help, there is NOTHING you have done which can legitimately lead to violence from her, despite your own problematic past, you don't owe it to anyone to suffer through the same yourself. This isn't penance.
If she isn't willing to immediately commit to nonviolence and seeking help for this, you need to GTFO and get on with life.
I'll go a step further and say you can't get married with her unless this is solved and, for god's sake, don't bring a child into this picture.