well she was trying to push your buttons to see if you had felings for her still

some girls are crazy enough to see if they still have power over you and by you running from her like that it showed that she still does have powre over you

looking back at it, you could have simply said. i dont mind having you as a friend but i dont want to hear what you do sexually with your boyfriend. if you wanna catch up on the friendship we missed out on thats cool. but lets keep the boyfriend topics away from our conversation.

and after you clarified like that and she still presses on to tell you things you really have no interest in. just block her. :)