Should I stay in this new college class with my ex-girlfriend that i want back?

I used to treat my girl like crap, really really bad, but honestly it was a two way street, anyways while she was faithfull but physcotatic i was easy going but a "wanderer", if you know what i mean.. i would have affairs with other women, no sex though just kissing and foreplay.. recently we had a one month break up, it was on my terms so i was good to go, I didnt feel that i miss her or nothing... One night a couple weeks later she starts knockin on my door at 3 in the morning and I had no idea who it was. She was standing there crying, so i took her in, and we knocked boots that night. Then she started pulling the same stuff i did to her, back to me, i was falling for her again, and she was treating me like ****, and being scandalous, but i know shes not having sex becuase of our past history i can quarentee that, so i want her back really bad and i ended up in the same math class as her for college, when i try kissin her *** lately it turns her away, but she talks and chases me when i act like im not interested.. So my question is should i stay in this class and not talk to her or sit by her, or should i switch classes if we make eye contact or hear eachothres names on role call?