[font="Tahoma"]The simple fact that your mother let her anger control her decision to make you out your sexuality to your father is rather saddening and while she may have said that she's read all your diaries and journals and whatnot, I hardly believe that's the case. My mom uses the same tactics for me and I call them "Omniscient Mom" threats- where your mother says that she knows things about you when she really doesn't and uses an empty threat to persuade you to do something she likes.
That said, I think the best thing to do is to grab a trusted adult who already knows this information about you or that you trust not to judge you harshly to be a third party present(Lawyers and Cops may be a bit extreme and for the ex post facto) when you do finally decide to reveal your sexuality. Now, in an ideal situation, your parents should understand and appreciate your independent choices as a young adult and value honesty above all things, but with the situation you described that might not be the case. Either way, I believe it's important for you to be open and honest, not for your parents' sake but for your own sake. You might burn a few bridges, but at least you have inner peace within yourself knowing that you were open to your family and that you're not living a lie that so many people (read: politicians) have done in the past.
Overall though, this little tiff seems like it was just anger and frustration that turned violent and caused people to say things they may not have necessarily meant. If you address this with your mother in a calm, adult manner- regardless of her reaction- then you can resolve the situation on your own terms.
Keep your chin up, kiddo! :)[/font]