During research for King Eochaidh I came across a very interesting ancient fable or story. It was so old it had been translated four times before being translated into modern English.
I know it’s commonly taught nowadays that they are not immortals. But according to the original stories about them they are immortals and most were not very nice beings. It’s was their offsprings with humans that aren’t immortal.
I read a story, a very old story where this woman was married to this man who was a fairy and he wanted out of the marriage but didn’t wish to break her heart so he died. Or at least appeared to be dead. So he was buried and moaned by his family but years later resurfaced in another village. His kids found him and dragged him back home to their mother who old and wrinkled by then but they held him capture and wouldn’t let him leave until after their mother’s death. He wasn’t counting on the kids finding him. Apparently according to the story he forget his children had some of his powers. That’s when humans supposedly discovered fairies are immortal and like mermaids lies to get out relationships.