Most Helpful Girl
I don't think your guy friend wants to be in a serious relationship, so I think you should stay loyal to your boyfriend. I do think you should be very clear to him. If you do really miss the guy friend and want to go back to him, then I think you should break up with the boyfriend, but try to find out if the guy friend wants to be serious with you.
Most Helpful Guy
You should not do anything that puts your intentions in question. Do not see your guy friend since that will send the message that your boyfriend is not that important. Do you really want to send that message?
Your actions send very clear messages. Be careful what messages you send.