Should my boyfriend attend my senior prom, or no?

I am a Senior and my BF of over a year just graduated from the same school last year. I attended his senior prom and spent nearly 600 dollars including a 400 dress, he told me last year he would attend mine next year. Now he randomly says it would be akaward to go to my prom and he wont go and doesn't want to talk about it, its my senior prom and it means a lot if he would go.