boyfriends ex girlfriend

So my boyfriend has a stalker for an ex girlfriend they have been apart for 4+ years and we have been together 3+ years. So she had been stalking me for at least 2 of those years because she's blocked on all of his social media. She went so far as to make a new account on Facebook and message him on his birthday (nothing to do with his birthday tho) going on about how she doesn't want him back, that she moved on, that she doesn't want to interfere with our relationship but yet sends this novel of a message. By the end of the message she's basically trying to guilt him back to her. He never read the message he assumed it was a happy birthday I read the message then went to my Facebook which I don't use often and sent her this
I'm so tired of her trying to get in between our relationship.