my girlfriend won't stop cheating on me?

Me and my girlfriend have been dating for around 5 months now, I had just came out of a separation from a long term marriage, so i was looking to have a lot of fun and wild times, I met this girl at work and she like to drink a lot and have fun (exactly what i was looking for) after a month or so we became serious and she slowed down on the drinking and so did I, we went out to a bar one night and I got angry with her for some reason and left I got about 15 min away and decided I wasn't gonna leave her there with no way home! so i went back to talk to her, come to find out she was in a van with another guy giving him oral sex! the next day we talked though it and decided it was just a drunken night and a screw up...we have been good for the last 2 to 3 month and this past friday night i had to work late so i took her to her moms to stay the night, the next morning i was suppose to pick her up and her come back to my house. I got a message early that morning saying She was going to Nashville Tn, will explain later!

ok i was ill at this point because i called her and she would not tell me who she was going with!....I had to work most all day saturday anyways so i went on to work very upset! about midday she called me and broke up with me saying she want to try different things. I tried to change her mind but she would not go for it and I let it go at that! That evening she called me crying and upset said she had made a mistake and it hurt not to be with me! so I held her all that night trying to calm her down, because i dont want to lose her.....two days later no i'm thinking I have made a mistake by staying with her because this is twice now that she has cheated on me, should i leave her or keep trying with her?