Is this normal and would you stay in this relationshit?

Well first off I'm engaged and my fiance is bugging me to set a date since its already been a year engagement. Besides being scared shitless to get married (which is a whole different story)...I just don't know if what shes doing is wrong? We were out at some restaurant she smacked me like 5 times in the face which doesnt hurt or anything I hardly even notice, but this random stranger said to me You need to get out now. My friends all say the same thing that she shouldnt be smacking, scratching, hitting me...but i tell them just to shut up and don't worry about it. I love the girl to death thats why I proposed, and I've known her forever, so my question is...if you had a guy friend or a brother or whoever and their girl was smacking them all the time for no reason would you tell them to get out? Is it really that big a deal...like would it affect a marriage? I mean most of the time I probably deserve it anyway, and one of my friends says I say that cause I was abused as a kid and don't know better. I think thats BS but now i'm not sure... what do you think? Sorry this is so effing long..