Relationships

I ushally don't post things but I need some advice. I'm bisexual and I have an amazing boyfriend who I love with all my heart but I went to a friends house and had sex with a girl, I cheated on him and I feel AWFUL so I don't really need to be told how terrible I am because I'm aware. My boyfriend is being really supportive and as long as I don't do it again we're okay. But. I'm scared because it felt really nice and everyone (even him) is always saying I'm lesbian because I'm not sure I'd date any guy other than the one I'm with. I don't want to keep him on the hook if I really am lesbian but I'm so bad at confronting my feelings. I really do love him but I'm not sure if I like dicks... If that makes sense... We've done some stuff before (not sex) and it was okay, I just don't know how I feel.