Could I Be Bisexual Forever ?

As of 2009 i have discovered that i was bisexual when i had a three way kiss with a girl and boy and i loved it. in the last year i have heard things about bisexuals are confused, and they are just going through a faze, and not all of them end there lives as a bisexual. these comments hurt my feeling because i know for sure im not trying to cover up being gay by saying im bisexual. I know that i like both girls and boys equally and i know im not confused. Other comments such as there is no such thing as a bisexual man really pissed me off. I love having the urge of being around boys and girls and i would just like to know could my sexuality change such as may i become gay or straight in the future. I don't want this to happen but could it?