My gf caught me kissing & am really scared from her

She caught me kissing her best friend but i really wasn't cheating , it's just that her friend was grabbing my trousers down there when she got in the room & that's why she thought I was cheating..so she threatened to breakup with me , so I slapped her & told her to shut up & listen because it wasn't what it looked like, so she got angry & beat me up so hard & forced me to apologize & kiss her shoes over & over ( she has a black belt in karate) . that's when I told her that I am dumping her & she got angrier & said that she was going to leave me anyway but now she wants to teach me a lesson & I don't know what she means by "a lesson " , I am really scared from her & I didn't expect that she could beat me up, What shall I do?

Put the internet to work for you. via Personal Recipe 2629979