I'm going to let another girl who isn't my girlfriend sleep in my bed
Is it because you don't like your girlfriend anymore?
Yes, I am annoyed by her and she's also really ugly.
I understand you are frustrated with your relationship but If you are not happy in your relationship then just end it outright, don't play games.
That's what mean girls do, right?
It doesn't matter what mean girls do. It's wrong to sleep with another woman when you are with someone.