First off you're just 16. you have no idea if you will marry this girl or not. things change minute to minute. secondly you know you had anger issues prior to being with her and knew what she went through. you turned around and horribly abused her. You are 16 and need to end things with her like an adult male, let her go on her way and you need to get therapy and work on yourself first before being with her or anyone else for that fact.