She has certainly done the rounds. She was the second wife of MIDIR, and their marriage caused no little jealousy in the heart of his ex, FUAMNACH. With a little help from friends, she magically changed ETAIN into a pool of water.
MIDIR, very perplexed when his wife went missing, started investigations on a Godly scale. To keep ahead of the game, FUAMNACH then changed ETAIN into a worm. And then a fly... but whoosh, the fly flew down her throat, and — as happens surprisingly often in these cases — FUAMNACH became pregnant.
Eventually ETAIN was reborn — as a mortal. Growing from a baby into she knew not who, she married a king called Eochaidh. But she really fancied his brother Ailill, which probably caused a little ill-will.
To cut a long story short, one day she met MIDIR again, had a memory lapse in reverse and fancied him something rotten. And vice versa. To untangle the whole marriage confusion, he managed to win her at a game of chess, and although we’re sure there’s much more, we should stop whilst we have a relatively happy ending.