Sounds like your new sponsor took on too much responsibility. I wouldn't talk to ER about it; what's the point? I would find someone who knows their limits and can stick to a commitment.
I would simply thank the other sponsor for their time and say you're going to move on - and here's where the real growth is for you: tell him why so he knows what he can do differently too, and there are no loose ends hanging.
Big growth available to you here.
You're doing great.
One more thing: you might consider actually asking God to bring you a sponsor who can help you.