Lord Byron, the chartered accountant

Unaccountable, by harriet_spy (Holmes, Watson, Irene Adler; PG)

"The first marriage I can forgive her. She was young, she was foolish, and most importantly, she hadn't met me yet. You can't expect a beauty like that to immure herself on the off-chance we might cross paths. Though she might have shown a little foresight."

Irene gets married again; Holmes reacts as expected. Perfect Holmes-Watson interaction, and an Irene who's still around, even when she's not.