The Selkie's Tale - Shadowling Shifters, #1

Seven tears cast upon the water summon the selkie, summon seal across the ocean, summon man from beast-liquid keys to break the curse. Freed one night every seven years, Ronin is doomed to repeat that cycle into eternity. Unless he can find a woman powerful enough to resist a selkie's irresistible pheromones and sex magick. Maille believes she lost reality between Maine and New Mexico. Between where she is now and where she should be.
She believes in facts, not magick. But facts can't explain how she wound up naked on a beach with the sexiest man she's ever laid eyes on. Or how she knows in her bones that losing herself in the passion Ronin offers is a path to disaster. It's going to be a long, hot, wet night. Caught between sex magick and a sexy selkie, disaster is inevitable for Maille. To break the enchantment she has to rely on the oldest magick of all-the power of love-drenched hearts.