What a friend!!!

What is your problem?
Why do you do this to me?
You tried taken my boyfriend
well baby, That wasn't gonna be
You flirt with him, and put on all this stupid shit
I getting sick and tired of every last bit
You lied, cheated and talked about me behind my back
Right now, friendship is something i really lack
I cant take it anymore
I'm through
you wont be so flirty now
when i get done with you!!!

My used to be friend is trying to take my boyfriend!! Do i step up or back off? Please comment and help me on what to do