I don't cheat. Never.
If you are in a relationship where you have made a mutual decision to be monogamous, then you should honour that. Otherwise let her know that you wanna play the field and if she is cool with that, then run with it.
My situation was similar to yours, where I was outside listening to music on my headphones cos I hated the music in the club. Went back in to find the chick missing. Someone told me they saw her go out.
Found her outside on the way back in with some white dude.
I was pissed and we were together for about six months at the time, but I gave her the benefit of the doubt.
After we were together for 3 years I found out from one of my boys that she not only made out with that dude that night but hooked up with him again a few times, as well as with four other dudes.
Then the bitch has the nerve to act like it was no biggie, since she didn't f*** any of them but only made out with them. Even got pissed off with my boys for telling me and with me for f***ing a few of her friends afterwards.
But yeah, she caused a lot of issues cos my mom loved her and so did the rest of the fam. Then when I hooked up with my new ex, she told the parents and people a lot of lies and caused problems in our relationship by having other bitches call her and shit.
So, I say, cut her loose. Not worth the trouble of getting in any deeper and then regretting it.