Well I assume he is a grown man and it would look silly if you confront her asking to leave your boyfriend alone like you are his momma. High school girls do that. Go to other girls and tell them to back off their boyfriends.

Since he didn’t put stop to her interference, he doesn’t mind it. I’d question why he doesn’t mind it?

I’d address it directly with my boyfriend and if he doesn’t stop this ridiculous behavior immediately and explains why he allows it, I’d look for a different boyfriend.

The issue isn’t this girl. The issue is your boyfriend.