<human>: Can you give me the gist of the text in a nutshell?

I have never been the controlling type in relationships. 

My girlfriend and I have been dating for about a year now, but we have previously dated in the past for about 3 years before taking a small break. 

A few months ago my girlfriend visited a friend at a college and attended "DayGlow" a rave/festival/electronic dance music type thing that tours at colleges. She ended up getting wasted very early on into the night and hooked up with some kid on the dance floor. I did not attend the festival and found out a few days later. 

She confronted to me about it and we had an arguement as I have loved this girl since early highschool and nothing like this has ever happened before. Trying my hardest not to end the relationship I established a rule that we weren't allowed to drink without our SO present, something we both agreed on. But lately, I constantly find myself asking her if she's drinking whenever she goes out to a BBQ or someones house. 

It's hard to cope when someone cheats. I have heard on /r/relationships that being too drunk isn't an excuse and merely don't like the idea of her drinking without me because of the fear of something like this happening again. She thinks it's slightly controlling but I am slowly working on building trust again. I completely trust her, I love her, but I do not trust her drinking without me there. Am I wrong? Am I taking this the completely wrong way?
<bot>: My girlfriend cheated on me while drunk without me present at a festival, I made a rule that we can't drink without each other around anymore. Am I being controlling or just trying to save this relationship?