Bad Magic (Hellhound Heat Book 2) by Sherilee Gray

Being publicly rejected by her mate isn't the worst thing that has happened to Sutton Ellis. Fate brought her and Jagger together when he saved her from a sadistic witch then guarded her until she recovered—but the gruff, stern hellhound insisted he didn't care what the fates wanted and left her for Hell. However, when a member of her coven goes missing and Sutton's fierce determination to find her friend lands her in life-or-death trouble, Jagger returns. And this time the sinfully sexy beast intends to be her giant, growly shadow. Sutton can't resist Jagger, or his determination to win her back. But her coven's safety must come first. She'll do whatever it takes to protect them...even if it means giving up her only chance at love...