How do i help my friend with her boy issues?

my friend jess started dating my ex boyfriend ryan.. jess broke up with ryan after he got too clingy but ever since hes been writing her creepy poems follwing her from her cles to my locker hugging her.. friday we were at school and he annouced they were dating again to everyone in gym cl. im embaresed cuz hes my ex too and i have to put up with both of them whining. someone help me please