Is it horrible to like my boyfriend's best friend? ?

ok guys so I have a boyfriend. we got together at prom (not "get together" as in "hook up" he just asked me out) and I really liked him. BUT we live like an hour away from each other and we barely ever see each other. we've gone on 2 dates in 2 months.. I knew his best friend before I knew him. his friend actually helped us get together. I was in his carpool after play practice and all and he's hilarious and just a great guy, plus he gets voice lessons from my dad once a week at my house so I see him more often than my boyfriend. anyway, I was at a graduation party and my friend accidentally told me my "love interest" was there (didn't mean my boyfriend she meant his best friend) and the weirdest thing was that he got kinda awk and I actually felt kinda funny. now I'm really confused because I love him, but as much as I'd feel horrible doing that to my boyfriend, I can't help but wonder what would happen... WHAT DO I DO??