Hello and welcome to EC, my first one get him at a good time, make him see you are still you. I do have a question how does he feel about LGBT in general?
Hey, and welcome to EC! It really depends on how your dad is. Is he anti-LGBT or is he OK with it? If you don't know, try bringing up a news story about gay/bisexual people and see how he reacts to it. If he turns out to be anti-LGBT, consider waiting until you're capable of supporting yourself to move out, if not already. If he turns out to be OK with them, maybe you can write a letter, or just tell him face-to-face. Don't hesitate - be confident! If you're young, he may pull the "this is a phase" card on you, but be firm. Tell him that this is not a phase, and in a few years (assuming you're younger) he will see - you're really bisexual, and it isn't a phase. And, DON'T be pressured to date women if you don't want to. You can date whoever you damn please, woman or man, and your dad can't do anything about it. Good luck. (*hug*)