Pretend You’ll Stay by Kathryn Kelly

Madison McKivitz has no explanation for how she ended up in a small Colorado tourist town. With only a driver’s license and a key to a condo she doesn’t recognize, she takes a job and hopes the memories of all the suddenly missing years in her life will somehow return. The last thing she needs is to fall for her far-too-handsome new employer.
Daniel Beaumont waited too long the first time he’d fallen in love. When his fiancée died before they could be married, he’d vowed never to put love on hold again. His new employee at the Durango & Silverton Narrow Gauge Railroad is easy to fall for but hard to pin down. How can he convince her his love is true when she doesn’t even know who she is?
Madison has forgotten her life. Daniel has never forgotten that love can end too soon. As they work together to untangle the mystery of her missing memories, can they forge a new, unforgettable love together?