20[M] party gets hot with 18[F] slut

I 20[M] was doing a DJ Gig for my best friends 18[F] birthday.
This happened 5 years ago almost to the day and it’s a night I’ll never forget.
The night was going well with not a lot happening.
The drinks were flowing, the food was great and everyone was vibing my music.
After a few hours I set a playlist to auto and relaxed to have some shots and down a few Jimmies.
The party at 10:30-11:00 pm was starting to calm down as most the people attending were former Christian College students.
All of them very proper, well mannered although bitchy.
I’m in the middle of some small talk with a life long friend of mine, when up struts the sexiest girl at the party. We will call this girl Libby, Clearly a little more than tipsy, passes me and my mate a bottle of Jäger, we each have a couple shots together back to back.
Small talk with Libby goes for a minute or two at most before she asked what my sleeping arrangements were for the night.
I mentioned I could just be sleeping in the guest bedroom for the night.
She replied, and I quote “you should sleep with me tonight”.
I moment of silence ensues, my mate walks off almost seeing ahead of time what would happen.
Libby and I straight up connect our lips and tongues and make out for a minute.
She backs off after it started getting hot and decided then to mention;
“I have a boyfriend”
I was the type of guy that wouldn’t fuck with relationships and respected women to a fault.
Cue in my best friend [Birthday girl] and her boyfriend (also best mate) screaming at me “SHE HAS A BOYFRIEND GET OFF HER”
Upon being made aware only a moment earlier of the fact I said
“True that, only just found out myself!”
I walked away and drama occurred immediately over what just happened. Almost like the place was burning down.