Not baby daddy but his ex

Hi all, I wonder if anyone has any advice or been in a similar situation. Basically my current partner has an ex who is constantly worming herself into his life (trying to). She has been contacting him on and off for a good few months now but it’s getting worse with her adding all his friends and family, messaging them and trying to sleep with his friends. She wasn’t the best girlfriend when she was with him (accused him of rape, would hit him, slept with his mates, cheated on him through their whole relationship, had numerous other partners at the same time, threatened his family and told them to die, tried putting curses and using witchcraft) just to name a few. So obviously I am not wanting such a negative person around. We have a child together and expecting another one later this year so now I have children with him I want to make sure this person isn’t hurting the infrastructure. She has a child herself (admitted to my partner and his close friend that she only had a child because he did) she is in a relationship currently and accusing her partner of strangling her, physical abuse etc. showing my partner police letters and records, social service files etc. then posting photos all over social media of them kissing and being all in love and no matter how many times he and I block her she is back trying to worm her way in. She tells him how she hates her child and wishes she never had him, how miserable she is and how she wants a new dad for her baby. I turned a blind eye at first but now I am worried about her negativity and persistence. She is messaging his cousin trying to sleep with him and go for drinks, messaging my partner, his sister, close friends, cousins. Any advice would be appreciated. Sorry it’s so long