Choose to Forget internal storage, how to recover
I can't help really, but I sympathize.  One commenter said "It's your fault".  No it's not!  Some stupid moronic programmer decided some idiotic protocol was required and the Moto G 2nd Gen quit reading any Micro SD card regularly, that is, encrypted for Andoid.  I had the exact same problem.  After upgrading to Marshmallow the damn thing quit reading my 64Gb high speed card.  So I dropped down to a 32Gb thinking it was compliant with manufactures specs.  Nope the 32 Gig failed just as much.  It would read the card for about 2 minutes and then stop.  I couldn't make a backup of the card, so you did the right thing.  Just start all over, format and get the BS encryption off your storage device.  If you ever format it again with Google encryption, well, then it's your fault. :)

Now root your Android roll it back to the previous build and you'll be able to shove a 128Gb Micro and it'll read it just fine.  Then you give Google a big FU for wrecking a perfectly functional phone.