<human>: Can you provide a brief overview of the text?

Throwaway for personal reasons.

Anyways, story time! I dumped my girlfriend of four years. She cheated on me with a guy she met a few weeks ago on the day of my friend's birthday. 

Backstory:  
My ex-girlfriend and I played plenty of League of Legends during our four years and we grew to like the game a lot. I, however, started playing less and less when I felt the need to start working and earning an income to support myself and my parents. She, on the other hand, is working on her Master's degree, which means I don't usually get to visit her often because of my work's overtime (I'm a temporary employee, trying to get permanent status), chores, and other stuff.

So on my friend's birthday, I was going to pick her up to meet my friends, but she didn't state that she was free until two hours before the party. I was waiting in line at the bakery picking up the cake for my friend, so I told her that I won't be able to make it and that she should find other plans (she was hanging out with the guy in the morning watching anime). After we discussed this, it took over an hour to pick up the cake and my friends, and we still got to the restaurant late (so picking her up would have made it alter).

Fast forward to the end of the night, she messaged me and said that she was watching the World Championships with the guy and his friends. Around the third or fourth game, she was dropped off at home and we just conversed from there. But the truth was that she went to the guy's house and they... y'know. 

Anywho, I found out because I usually pry into her stuff in front of her while hanging with her (curiosity kills the cat). I basically read the conversation she had with her best friend about what they did and etc etc.

And that was it. 

I wish the two of them the best of luck.
<bot>: I'm a douchebag for prying into my ex-girlfriend's privacy and I dumped her for cheating on me.