I really hate the whole "if he did it to her what makes you think he won't do it to you" because the reasons that it happened to her could have been because of something she did and who is to say that I would make that same mistake. I know it's not often but people change. Everyone makes mistakes and people make choices because they have hope that the outcome will be different so don't tell someone they'll end up like the last one because that's definitely not always the case.