Curious, straight, or slutty? And what to do! Help me please!

Okay, so here's the deal. I am 18, I've been in a relationship with a man since I was 15, and he is amazing and I love him to death! However, I think I am interested in girls as well. But I don't know if I'm just one of those slutty horny girls or if I'm actually maybe bi.... I've talked with my boyfriend about this and he said that he would be okay with me experimenting as long as he knows. But I come from a small hick town. I don't have anyone to talk to about this. I don't know if I should experiment because it might hurt my guy, even though he says he's good. But he really does want me to be happy, and is okay with me trying something. I'm definitely into guys, but I am also kinda attracted to females... Before I try anything oth a girl I kinda want to just talk to a girl that is bisexual and maybe get some advice? I'm confused and I'd really like help.