>>1 I see. Well even if youre bisexual, its wrong to love your bestfriend if you already have a boyfriend. Its still cheating. So its either you be loyal to your boyfriend or break up, then be with your bestfriend. Still, you have to know whether your bestfriend is into you or not. And please be sensible when leaving your boyfriend.
Another possibility is that you three dont mind an open relationship. Threesome, I suppose. Thats up to you to find out.
Either ways, make a sensible decision and you will be alright.