Replacing a tub spout – easy for anyone but me

When I was redoing the bathroom, I found an extra tub spout, with adapter. It sure looked better than the old one! So last night I decided to make the swap. It’s a threaded kind, so if I had a charmed or even normal life, it would be a matter of unscrewing the old, wrapping the threaded connection with teflon (or plumber’s) tape, and screwing the new one on, as shown. Unfortunately, neither the original threads or the adapter’s threads matched my connector so now I just have an empty spout sticking out of my wall until I can find the right spout at BigBox (if it exists) or get a plumber in to put a standard connector onto my copper plumbing. I tried to put the old spout back on, but it was so corroded that it literally fell apart when I took it off.