I'm afraid of my partner...?

My girlfriend beats me. It started as a little kink she had when we were being intimate, she'd sometimes slap me in the face and stuff. Since she's about a foot shorter and 100lbs lighter than me I thought nothing of it and let her indulge. Recently though she's been smoking quite a lot of crack and she beats me up all the time. Last night she wailed on me with the telephone receiver which chipped one of my front teeth. I really love her, but I'm afraid of her and I'm ashamed to admit it. Does it make me less of a man if my girlfriend beats on me? Please advise.