The Bailiff and the Mermaid

Pashtin is a null -- magic doesn't work on him, and he can break or suspend spells at a touch. Overall it's been more good than bad, despite the risks and inconveniences; it was his way out of poverty, to a good job as bailiff of the Wizards' Court. But now his gift has become a curse; he's falling in love with a woman he can't touch, because he would break the spell that's keeping her alive. And worse, she's a mermaid; even if they figure out how to touch without her dying, that's
only the first of their problems.

63,000 words, plus glossary of proper names, afterword, etc.