The Autumn Castle by Kim Wilkins
Christine Starlight lives in an artists' colony with her lover Jude, whose patience and beauty have eased her battle with chronic pain.
But Christine begins to be haunted by childhood recollections of a little girl's disappearance and the flapping of a blackbird's wings. Then her world is rocked by the return of a childhood friend.
Mayfridh rules over a land where a wolf is the queen's counsellor, fate turns on the fall of an autumn leaf and mortals feel no pain.
As Christine becomes addicted to Mayfridh's world, so Mayfridh grows addicted to Christine's, falling dangerously in love with Jude.