personally I think you did the right thing. But yes you now need to step away from it all.

Like you said, you saying anything didnt start the ripple, her mum was already going to say something to her. You havens said or done anything with malice, you are looking out for her safety. You arent trying to bring their relationship undone so you can have him back. You are looking out for a young girl who probably doesnt know any better.

Let it run its course now, take some steps back, and ejoy your life knowing that you got rid of him xo