Literally did it on impulse without even thinking about it so I wouldn't chicken out, so I blurted it out.
I said "I'm bisexual. I like both men and women. No more anti-gay stuff from you, ok?".
He said, "oh go away, you don't know what you like". I think he'll understand eventually, he needs time to think.
EDIT: Showed him this thread.
I said: "Look, this is what I said to you, these are my online friends who are happy for me that I came out as bisexual."
He said: "Oh you don't know what you're talking about, you've never had sex with a man or a woman before, until then you'll never know."
And yeah, I am still holding on to my v-card at 26. I was insecure about that years ago in high school, but I'm honestly glad I've waited to mature first.
Maybe this is too personal, but I just so happen to be sort of falling in love with a woman right now, and that kind of makes me sad because if that goes well my dad is probably just gonna keep denying I'm bi until he dies of old age.
Dont ever get into the trap of thinking you need to date say, a man to 'validate' your bi-ness - bisexuals are valid even if they've never been in a romantic or sexual relationship with anyone, you know yourself what you're attracted too.