I'm in a relationship for a year now and my best guy friend says he really likes me. what do i do?

i really do love my man and he is such an amazing person. i love him too much to not be with him. but here's the problem, at work my best guy friend has fallen for me. i have had him in the friend zone the entire time but now I'm starting to freak out. i don't know what to do. i love my boyfriend so much and it hurts to even think to leave him but my guy friend just keep insisting about how i deserve better. my boyfriend is the best for me. what should i do? help!