Hi moniker, my dh has bipolar II (they think) with some psychotic features. A bit different from your situation as my dh was diagnosed 18 years ago and has been on meds ever since, but it is hard, both for him and for you. I think it is very difficult if he won't acknowledge it is hard for you, and I hope you are finding some response here that helps you - certainly looks good.
Stuff that has helped him and me includes:
Mood diary: dh scores his mood from 1-10 every day and records it. It is amazing how the patterns and triggers leap out, although you will usually know what they are anyway. It could allow your dh to see them too. From what you say I doubt your dh is the kind of person who would really want to do this, but I REALLY recommend it.
Books: the two that have helped me most are An Unquiet Mind by Kay Redfield Jamison and \link{http://www.amazon.co.uk/exec/obidos/ASIN/0824729358/qid=1147356403/sr=1-24/ref=sr_1_2_24/203-8206136-6294354\Bipolar Disorder} by Kaspar Siegfried (I think it's this one). Both are by psychiatrists so both have a pro-meds approach (Kay Jamison says she believes it is malpractice to treat bd without them) but KJ also has bd herself. You don't have to agree with all of it to find helpful things in some of them.
Acceptance - I feel really lucky that dh had long accepted his diagnosis by the time he met me. I have at least one friend who would say he is too compliant with his meds, but I am so grateful that he is, personally. I think it can take a long time for both him and you to accept such a major diagnosis and translate it into what it really means for you. Don't persevere with books, groups etc that don't feel right for you, but don't give up on searching, if you can, or on the things that work for you.
Awareness - my dh tried fish oils and promptly got gout! Be aware of any physical symptoms that do result from changes like this.
CPN - if your dh gets referred to the Community Mental Health Team and is willing to see a CPN, they can be real gold dust. The guy my dh sees is just genius.
Therapy - possibly useful, possibly not. Your dh should get somebody good via the NHS, don't muck about with someone who hasn't got a lot of experience in bd. My dh thinks his therapy probably hasn't helped him that much, but he only really had much of it after 17 years of illness when he'd learned all the stuff himself anyway...
Caring is tough on you - that needs accepting too. Do go to your GP.