In the original Aladdin story there is a genie of a ring and in a bottle. I don’t know what that means in OUAT myths though. Could the ring be something that came from a wish and the inability to love/inability to die is tied to it?
Maybe Jafar’ mother used a wish to save herself or become a healer and that magic ring keeps you alive but at the cost you cannot feel love for others? I don’t know why but I feel like if magic cannot make you love someone it does seem like it could make you stop (by taking away memories or perhaps even directly removing a heart).
“If I had a world of my own, everything would be nonsense. Nothing would be what it is, because everything would be what it isn't. And contrary wise, what is, it wouldn't be. And what it wouldn't be, it would. You see?” -- Lewis Carroll, Alice's Adventures in Wonderland & Through the Looking-Glass