18m cheated on my girlfriend

So for some context, I’m a freshman in college and I’ve been dating A for about 3 years now. I met K at the beginning of the year and there’s been tension between us ever since even though she had a boyfriend (S) and I had a girlfriend. We went out to the bars one night with me my roommate, k, and her roommate. As the night went on Ks roommate got a little too drunk and she had to go home early. The three of us bought shots and had drinks until it was time to go probably around 2:00 in the morning. K needed to get home but her room was on the opposite end of campus and we offered her to come stay on our futon since it was closer. When we got closer to our building, my roommate got a text from a girl asking him to come over. That left K and I. I could tell she was feeling the drinks a little by now and I was too. I took my shirt off and changed out of my jeans into some sweat pants. We’re close friends and she’s seen me change before but I always had underwear on. She asked me to borrow and t shirt so I threw her one. She put on the t shirt and took off her bra. I could see her hard nipples through the shirt and I was getting horny. As I was making the bed she had a question. “Can I ask you something?” I replied “sure anything.” “I just really want to know how big it is.. it looks way bigger than S..” At this point I was a little shocked and I didn’t know what to do.. we were both in relationships but fuck she looked so good. I drunk replied “bigger than your boyfriends” she told me she wanted me to prove it. She got on her knees in front of me. “Would your girlfriend be mad if she knew I was about to see your big cock?” She said looking into my eyes. “Would she be upset if she knew how hard you were while I’m on my knees in front of you?” At this point I could care less. I said, “Am I bigger than your boyfriend” she said this is the biggest cock I’ve ever seen and she pulled it out of my pants. She told me to pull out my phone and and take a video so I did. She started jerking me off and licked the tip of my cock. “I want to taste all of your cum” she said as she started licking up and down my shaft. She started throating me and I fucked her face on camera. After a while she told me she needed it inside of her. At this point I had never been with another girl except A but I was drunk and I didn’t care. I took another video as I put it inside her and she said “I bet my pussy is way tighter than As. I want to fill you up with that big cock S can’t give me.” Her pussy felt so good. Her tight lips gripped on my big cock as I slid in and out of her. I flipped her over in doggy and gave her back shots. We went back to missionary I took a video of us fucking and she started kissing me and telling me this was the best she’s ever been fucked in her entire life. She told me she was going to cum and she wanted me to cum inside her. I started getting faster until I thought I was going to bust I shot rope after rope of cum into her and she started cumming all over my dick at the same time. Best sex I’ve ever had. To this day nobody knows.