It could just take longer for him to figure out it's okay. He might not.
I can tell you my whatever-it-is was about eight years in the making (nine? I can't count very well). I was with First Boyfriend and Current Boyfriend was our very dear and good friend. They worked together. Then I broke up with First Boyfriend, and after a bit, started going with Current Boyfriend. Then I broke up with Current Boyfriend (and made him move out). Now, they're both my boyfriend (lucky girl). I wasn't going at it with intention, but here it is.
I know it's painful. I recommend working on compersion, being happy for him if he finds happiness in new loves. Keep on loving him, even if he isn't your boyfriend (now).