I'm not sexually attracted to my girlfriend, should I break up with her?

I originally planned for it to just be a 1 night thing. I was in a dry spell and was desperate for a companion. But I felt really bad for her because she was in a tough situation and needed help getting out and starting a new life. I helped her get a new place, helped her buy her first car, and other life changing events. She says that I'm the best boyfriend that she ever had. She's a really sweet girl, great personality. She cooks and cleans and rubs my feet when I ask her to but here's the thing: I'm not sexually to her. Her skin is too dark, her nose is too flat, she's too short, she has stretch marks from her child birth, very little muscle tone, and she has a really thick asian accent that annoys the hell out of me. My ideal girlfriend would be tall & light skinned with a tight body and abs or atleast no stretch marks with long hair, would speak clear english, and would be more confident with herself. My girlfriend often grabs my crotch in the Hope's that it'll put me in the mood but I find that I'd rather go into the bathroom and jerk off thinking about my ex girlfriends. My mom tells me that looks fade aren't important and it's the personality that counts but I call bullshit. Why sacrifice 1 to get the other? If I'm going to be happy and choose a life partner shouldn't she have BOTH the looks and personality that I want? If I stay with someone who doesn't turn me on isn't that relationship doomed to fail?