Running to You by Robin Patchen

Sam never understood why Eliza left him five years ago, ghosting him without explanation. He’s avoided romance ever since, focusing on building his business. Money might not keep him warm at night, but it can sure buy a lot of blankets.
Then Eliza shows up on his doorstep and throws herself into his arms. She can’t explain her bruises or the head injury that’s left her with no memories of the past five years, including their breakup. No matter how good it feels to hold her, though, there’s no way he’s getting sucked into romance again.
He’ll deliver Eliza to her mother, and that will be that. But instead of finding her mom, they’re met by two attackers and barely escape alive. Despite the danger to his life and his heart, he can’t leave Eliza to fend for herself.
Together, they embark on a journey to reconstruct her past while evading the men chasing her. As Sam and Eliza close in on the truth, their romance reignites, but her secret threatens to destroy them both.