Ignore the guy you think is really cute and think about the guy you have right now. how do you think he's gonna take it. "yeah sorry but im dumping you for this guy i thought was really cute and have liked more than you ever since the fourth grade". Dont do it.
Since you already have a boyfriend, you should stick with him and forget about the other guy. It would be unfair for you to dump your boyfriend for someone else, since you have been dating for quite some time now.
How do you feel about your current boyfriend? Is he good to you? Is he always there for you? Does he support you? And most importantly: Are you happy? Why dump someone who is good for you and makes you happy just because some new guy likes you? Yeah these new ideas your having might be exciting, but think about what will be best for you in the long wrong. Only you know what your heart longs for.