Thanks for the replies all
I tried cutting into the "ring" with a razorblade this morning, it wouldn't even come close to cutting through it.
That's about the only sharp tool I've got available
I took a couple pictures to help illustrate the problem, maybe I'm just being stupid?
I copied the two pictures and edited them in their own files so that I could draw on it and annotate exactly what the problem is.
That metal-gray-colored ring makes the size of the pipe significantly bigger, so none of the 1/2" connections will fit onto it but the 3/4" adapter just slides on and off because it's too big.
Should I make a run to home depot and buy a dremel tool and try to use that to cut it off?
EDIT: In that second picture (the side-view one w/ the white boxes for text), the text totally doesn't show up. Sorry about that. The far right bracket is the "ring" and the bracket to the left of that is the area of the pipe that is threaded and still has some teflon tape on it.