My girlfriend has cheated on me and I don't whether to give her a second chance

To start from the beginning me and her had a talking stage which lasted 5 months cause it started with us hooking up and not being ready for a relationship but we caught feelings along the way and ended up dating. Before we were talking she's had a big h*e phase and would make out with a lot of people at the club and sleep around to deal with heartbreak from a situationship before me. She stopped doing that once we started hooking up.

About 3 months in of us talking once we both were aware of our feelings and confessed them, we went clubbing together however each of us were with our own friends. The next day she tells me that she made out with someone at the club and it did hurt me because a day before she was telling me she only wants to kiss me. I could tell she really regretted it and so after a few weeks I forgave her and we continued talking.

She has always been really reckless with her drinking so I said to her once uni starts again she has to prove to me that she can get blackout drunk and stay loyal to me and she agreed. After some times she managed to gain my trust back and I felt secure she wouldn't do anything and only has eyes for me.

Under 2 weeks ago she had a Halloween house party back home. She didn't know this but I pushed her to go because I wanted her to prove to me she can get blackout drunk and stay loyal to me. I knew she was going to get really drunk because I wouldn't be there to help her with her drinking. She was wearing a joker outfit and she asked if she should button up her shirt and I said no leave it unbuttoned like you had it with me when we went to the club the other day and just tuck it in. I knew the guys back home would be looking at her cause I knew a few fancied her. I was 100% sure she wouldn't let anything happen like I felt so sure.

And just like i predicted she did get really drunk that night. Even though i was messaging her to slow it down with her drinking and she didnt listen. The next day I meet her and she tells me that one guy tried to kiss her but she pulled back. We then cuddled for few minutes and I knew something was wrong my gut was telling me something isn't right. She was holding me so tight. And then we get up and like in a movie scene we look at each other and I sensed something wasn't right. I just asked her what did you do. And she starts sobbing and says they made out. She didn't tell me the whole truth until two days later. Apparently they started making out and then they went to the bathroom together where he played with her b**b and a*e her out.

I do believe she regrets it as she has shown a lot of remorse but the damage has been done twice and I don't whether I can recover from this at all. This time she went all the way and followed him to the bathroom. Like it hurts like hell because i would never do that to her. Any advice??