Speaking from experience, dating someone with toxic family members is tough. Especially if your SO is divided between you and their family. From an outside perspective, it can be fairly obvious that he's unstable. But she grew up with that, and she probably has at least some fond memories of him she doesn't want to let go of. You have to make a choice. Doesn't have to be right now, but there will be a time when the balance of having to deal with her family outweighs the improvement to your life that you get from your relationship. My advice would be to distance yourself from him. Then, discuss with your gf what her future plans are to deal with her family. With violent, toxic people like this, sometimes the only way to deal with it is to cut them off. Is that financially/emotionally feasible for her right now? Is that what she wants to do, eventually? Or does she want to see him change? People can change, but it's rarely successful. Cutting them out of your life, on the other hand, is rough, but it works. You should talk to her about these things. Make up your decision what you would like to see her do. After all, if this relationship is serious, they could become your family roo. If you two don't agree, this could become a deal breaker down the line.