Ah ha now my chance to help(maybe). Lets take the bi-polar label out of the equation. Now ask yourself if this gentlemen did not pay for dinner, did not contribute to he relationship, did not provide you with a shoulder to lean on when you are in need of one to 'cry' or just rest on would you still be with him? I hope your answer is no.
I don't know you well, but from your correspondance you seem to be someone who is very caring and wanting to help others and 'make things better', it sounds like with this relationship you are taking yrou work home with you.
I am one to talk because I hate conflict, but have you discussed these things with your fella? Unfortunately guys and gals are not mind readers. If he doesn't know what is bothering you than he can't work on fixing it. If he does know and he chooses not to change his ways, then I am afraid it is time for you to decide whether you are satisfied or whether it is time to move on.
Remember you deserve to be happy, and there is someone out there for you. Relationships are give and take, not just take, take , take.
Hope this helps. Take Care