<human>: This is the first time I've ever cheated and I feel terrible. I know, I'm an asshole for cheating. I never thought I'd be "that" guy but here I am.

On Friday night, my girlfriend and I went to a Halloween party at a mutual friend's house. There were a lot of people there that we had never met, so we made quite a few new friends.

At one point, her and I got split up. She was hanging out with her girls and I was in the backyard talking to some new people. There was this one girl in particular that kind of followed me around for awhile. So we started talking and hanging out. She was really flirty and made it pretty obvious that she was interested in me. I mentioned my girlfriend a few times but that didn't seem to phase her.

At one point, she said she was cold and needed to grab some pants out of her car. (She was wearing really short shorts for her costume). She didn't want to go to her car alone, so I agreed to go with her, which was a mistake.

To make a long story short, we ended up fucking in her backseat. We exchanged numbers and went back to the party like nothing happened.

This morning, the girl texted me and asked me what I was up to. Basically, she said she likes me and wants to get together again. She thinks we have "chemistry" and is interested in a possible relationship. I'd be lying if I said I didn't like her.

I feel guilty. My girlfriend of two years would be devastated, so instead of telling her what happened, I'm thinking of just breaking up with her and dating this new girl. 

I'd appreciate any advice you have to give. I realize I'm opening a can of worms here, so I'm expecting some hate, which is fine. For those of you that have cheated, what did you do to fix the situation?

Could you distill the essence of the text into 1-3 sentences?
<bot>: I cheated. Now I like the girl I cheated on my girlfriend with. She likes me back and now I'm thinking about dumping my girlfriend.