I'm so confused!

I've had a boyfriend for a year and a half...but over the last few months I've been really attracted to this girl. She and I have an amazing connection and she really likes me. I care about my boyfriend so much and i never want to hurt him, but I can't stop thinking about this girl. I don't know what to do. My bf knew i was bi before he started dating me, but he never took it seriously. I'm so confused, being bi doesnt mean the best of both world like some people think....ultimately a person has got to decide on one person. Can someone help me out , give me some advice?