I disagree with the majority I would have never of tried to get involved or tried to help the girl in anyway because I would feel that it would come back and bite me on the bum, and what 18yr old is going to listen to their family, friends or ex-girlfriend when they are in love?
But I'm not saying that you shouldn't of done it, because I in no way have been in that situation or understand the whole story. So my feeling is you should do what feels right for you and in your case you felt you needed to protect this young girl, which i can totally understand but also you need to protect yourself is what im saying.