Under the Mistletoe by Summer Donnelly

Ever since the night Thorne Evans was shot in a bar fight over her honor, Piper McAvoy had been trying to make amends. After a disastrous date that resulted in him never calling her again, Piper had finally given up her pursuit.
As the oldest son of a long and respected magical family, Thorne Evans had the responsibility to marry and produce daughters. But at thirty-five, he wasn’t quite ready to settle down. Getting shot, however, taught Thorne that life was too short. But when their first date ended with Piper announcing she didn’t want children of her own, Thorne knew there was no future between them.

When a Christmas Eve leaves them with just each other, the twinkling lights of the Christmas tree, and a sprig of mistletoe, can two opposing hearts find enough common ground to let love grow? Or will their conflicting goals rip them apart?