I think I like girls but... I have a boyfriend

I know this is kind of long but hear me out. So I've been dating my boyfriend for almost a year now and I haven't fallen in love with him. He is the most perfect dude anyone can ask for but... I just don't feel the same way he feels for me. I came out to him as bisexual when we were broken up but... I got back together with him because I'm just so confused. This dude just loves me and he is a part of me he knows me so well and I just cant break up with him and never talk to him again. 
Recently I've been more interested in girls. I stare when a cute girl passes by, I see myself in a relationship with a girl. I want to try experimenting and I want to come out but... what if I don't like girls like I thought I did? Like what if I just broke this guys heart for no reason? And what if I do come out and nobody accepts me, because my high school is very judgmental and I'm just scared of what people would say. Any advice?