Oh, Summertimegirl--this illness changes people into someone you don't even know--someone they don't know--are you prepared to take him as he is? It sounds as if he isn't ready or willing to come back and you may just have to accept that and move on. I do not mean to seem harsh, but realistic. My BP daughter was in a long term relationship with one guy--"the love of her life" for a few years..then had a manic period, broke off with him and never looked back. He was devastated, and she never, to my knowledge, ever gave him any kind of explanation. Just "go away". Pretty harsh, but often people with BP are pretty harsh--they don't mean to be, they just can be, they are so wrapped up in their own feelings. She moved on to the guy she's currently with and I hope when she dumps him (and she will) he handles it better.
If you want advice, I'd have to say, go ahead with your life w/o him in your plans. Sounds like he's creating a new life for himself w/o you, you should do the same. As for manias and coming down off of them--everyone is individual. Some people take months, some take days, others, just hours. There's no set rules for that, so don't look for any.
I'm so sorry.
Liz