Well I think we all are confused. Before any contact between her and your son I think you need to sit down with her and clear the air about the problems between the two of you. If she is a problem then you have every right to not let your son see her. Maybe this was a one time thing between you two or maybe it has been ongoing. But first and foremost would be for the two of you to get on track before you bring your son into it. If you feel you can't get on track with her then that should be a clear indication that your son should not be involved with her either.