So You Forgot You Love Me by Elizabeth Maddrey

Her body has healed. His heart is still broken.

Tyler Shaw thought he had it all—his dream job, an amazing girlfriend, and a proposal plan that was sure to be a memory they’d tell their grandkids. Then the accident happened. Rather than a few weeks for her to heal, he’d been dumped and told—in no uncertain terms—to stay away.
But he can’t find a way to move on.
Nine months ago, a high-speed accident left Danielle Hicks in the hospital days before Tyler was planning to propose. She recovered from her injuries just like the doctors anticipated and returned to work. But her memory is still spotty and she’s adjusting to the fact that it may be permanent. She doesn’t need Tyler’s constant, subtle reminders that they used to be an item when she’s not sure if he’s for real.
A big project at work provides the perfect opportunity for them to work together. If he can’t awaken the memories of what they had, will he at least be able to convince her to try anew?