You’ll probably want to throw her out of your house as soon as she tries to take her or maybe your hands itch to send her a message to leave you alone, but it’s a very serious mistake if you do. Firstly because you will cause a conflict with your child, and secondly because you are not teaching him to resolve this type of situation that could be repeated in his love life.
Unless it is an extreme case, your child is in danger or his emotional health is disturbed, and you undoubtedly must act, limit yourself to being a discreet detective and remember… be his confidant.