IF he is NOT doing HIS part.
There really is Nothing you can do.

I am a big time Bipolar and very difficult person to get along with -

So from my mouth I tell you

Don't let him pull you down..... I know you have love for him....

But like a tree if you put too much weight on it - it will eventually fall over...
So if you take on HIS issues you may find yourself baring depression.

It sounds like you've done all you can - Which in itself is GREAT.
Most people don't even try...
If you believe you have then it is time to step back - just my opinion