i don't see why you would need to tell them, they will get the hint when you bring a patner over of the same sex. I don't tell my parents that i'm Asexual. i don't date or talk about either gender that way.
I'm bi. I've been thinking of a way to tell my parents, but my dad seems a bit...homophobic. What do I do?
I would say only to tell your parents if you feel safe in doing so. By safe I mean, you don't think you're going to get kicked out of the house, or harmed in any way. This is especially true if you are unable to support yourself.
If you don't feel safe, keep it under wraps until it is more safe to do. Living who you are can be very difficult when people are not accepting of it, but your safety should always come first.