Look at it this way, you are lucky to be bi, what if you had zero attraction boys? I, like bixkf, am bisexual but have been in a monogamous relationship with my wife for 17 years.
I am still bisexual, that will never change. I am comfortable with that, you can be too. You just have to decide to be ok with that attraction. Nobody needs to know you are attracted to girls as well. What the family doesn't know won't hurt them.
And forget trying to change, it won't happen.