Human imperfection is common into our well-being. There are times when you're dealing with a toxic boyfriend/girlfriend or partner in life and it's getting complicated when the situation getting worst. Especially when abuse will get involved in a relationship that you became a victim and being imprisoned emotionally, psychologically and physically from your abusive partner. I've seen lots of people in real life experiencing this kind of problem. Toxic people formed usually where and how they grow up in their own environment, and they will bring it with them when they have a relationship.
It's good to educate ourselves in dealing with negative partner. Communication is one of the best tool to solve problem in a relationship and the best way to communicate with your partner is to wait when the situation gets calmed. You cannot argue with your partner when there's so much in your head and will accidentally say things when you're not suppose to say it and another impending problem will arise. Drugs and alcohol intake are also a destroyer of an argument that the thinking process and judgment is not in appropriate way, so it's better to clear your mind and sober to the state of being rational when it comes to argument.
Sometimes it's impossible to changed the behavior of your partner, but changing yourself is possible. Identifying the positive side of your partner and being grateful with it might help, bringing positivity to your partner attracts positive energy that brings harmony. And if that doesn't work, letting it go and moving on from your partner should be the last resort.