boyfriend cheating with me?

GIRLSSS I NEED HELP

I’ve been messing around with a boy for a while now. We basicly have done everything.

He always told me he doesn’t have instagram bc that’s stupid.

GUESS WHAT

I found his instagram like an hour ago and HE HAS A FREAKIN GIRLFRIEND

Should I tell the girl about his boyfriend?

I don’t know If I’d wanted to know if my bf was cheating on me

EDIT:( dont wanna comment bc i dont want mean comments)

im obviously not staying with him. I just dont know what to do with that poor girl.