Need some advice

So I have this Co worker that I'm attractive to...he is one of my best friends and I can tell him everything...well September 2014 we started spending time with each other and he told me he just wanted to be fwbs...he is the only man I have been with since last September...I've tried telling him how I feel...he told me he don't want a relationship and that I deserve someone who buys me dinner takes me to the movies...he is the only guy I want in my life...I don't want to lose this guy...he is the key to my happiness...what should I do???