SUBREDDIT: r/relationships
TITLE: I [21/M] just broke up with my girlfriend [21/F] of 5 years due to a cheating incident with my best friend
POST: It was my 21st birthday party. At the end of bar hopping my best friend (21/M) and girlfriend (21/F) came back to my house. We hung out for a little when I decided I wanted to go to bed after a long night out. I went to bed while my bestfriend and gf stayed up. They fucked and I was informed by my gf when I woke up. Later by my friend via text.

I'm an absolute wreck. I just lost my two best friends. I can't sleep or eat. This...I don't know how to handle this. I can't talk to her. Five year's on the 4th of July. A fifth of my life. Gone just like that. I told her we are over and packed all her stuff and told her that she should pick her stuff up at 12pm tomorrow and that I won't be seeing or talking to her. I'm trying to be emotionless and mature. My family is devastated and I can't stomach telling them why it's over and they want to know so bad and are very persistent. I told my father in confidence but....I just don't know what to do or what's real anymore.
TL;DR: 
Girlfriend of 5 years cheated on me with my best friend after I fell asleep after my 21st birthday party and I don't know how to handle it.