If you obtained the passwords illegally through some hacking assistance program, then I do not believe those emails are submissible in court. I think if you invaded privacy without their knowledge, then it is inadmissable (and frowned upon). I could be wrong, but I think that’s what I remember from an earlier post here (though I cant find it to show you).
On a side note. If she does not have PROOF POSITIVE to her allegations, then don’t worry about what she says. In fact, no proof could mean she could be guilty of defamation of character (of you). To make personal allegations (like abuse or whatever), she’s going to need some hard proof if she wants to use it in court. Emails aren’t proof. Other folks who think badly on you aren’t worth your time worrying. The truth comes out in the end…so don’t worry.