Second Act by Diana Xarissa

Terri Briggs is happily divorced. She and her ex-husband get along reasonably well as they work together to raise their son, Thomas.
Lucas Hogan owns businesses all over the world, including several in Ramsey. He’s never visited the small town, though.
When Lucas does pay a surprise visit to Ramsey, he has a shocking proposition for Terri. His dying mother wants to see him happily married before she dies, and he’s prepared to pay Terri for her time if she’ll pretend to be his fiancée for a few weeks.
Although Terri hates the idea of living a lie, Lucas insists that it’s just a bit of harmless play-acting for a good cause. She reluctantly agrees and the Ramsey Harvest Festival gives them plenty of opportunities to be together. When Terri finds herself falling for Lucas, though, she starts to regret her decision.