The reality is that you are bipolar. Your BF can deny it all he wants, that does not make him right. He may benefit from a session or two with a Pdoc to explain your illness, how it is diagnosed and what behavior to expect from you. If he cares about you he is probably scared and upset and knows no other way to express his feelings. It may be a difficult road for you and him as you adjust your life to this new illness but in the end I hope it is worth it.