His Magical Bride by Merry Farmer

Haskell, Wyoming sheriff, Trey Knighton, has never considered himself the marrying sort. He’d rather face down a whole pack of bloodthirsty outlaws than give his heart away, especially after losing his entire family to cholera as a boy. Love is just too big of a risk. But Howard Haskell has twisted his arm into sending away for a mail-order bride, and he’s too much of a gentleman to turn her away. He’s convinced everything will be fine if his marriage is in name only.
Talia Lambert is overjoyed not only to have a home and a husband at last, she’s eager to put her skills as a nurse to good use. She gets her chance only days after arriving in Haskell when influenza breaks out. She is happy to be of use, but as the attraction between her and Trey grows, so does Trey’s fear that disease will take her too if she continues working with the sick.

But Talia and Trey face a danger more sinister than disease when her healing skill is labeled as witchcraft. Trey must defend Talia against the ridiculous accusations, even as he overcomes his fears to find with Talia the love he has always been missing.