My girlfriend cheated on me twice in one night

I dated a girl only for a month but we were good friends for a year before. We started dating again recently, but after one week she cheated on me with my bestfriend and another guy. Last time we broke up she went with a guy straight after the break up, which really hurt me.

This time I had only been with her 2 hours before at a house party, when she got a bit drunk, and stayed over at a friend's house. My so called mates went with her. She called me straight after it happened, but really should i have accepted that? She told me she loved me, but I had only been with her 2 hours before she got with two other guys. I took her back, and now shes no longer interested 2 weeks later. If she cheats on you once, fair enough she was drunk, but now for a second time? Forget this girl.