Before She Knew. Falling Leaves Series, Book 1, #1

The one who got away is back-and this time, he's not letting her go. A small-town second-chance romance filled with first loves, forbidden longing, and the kind of chemistry that never fades. Rachel thought her love story with Brad was over. Now a stay-at-home mom and artist, she's fighting to hold together a crumbling marriage no one else sees. Her husband's secrets run deep-and so does Rachel's loyalty, even as her heart feels more and more like a stranger in her own life.
She never expected her latest art commission to bring Brad back into her orbit . or to awaken a spark she thought had long gone cold. Brad let Rachel go once-and he's regretted it ever since. Running into her again stirs up every what-if, and every memory of the only woman who ever felt like home. But with Rachel still clinging to a fractured marriage and battling fresh betrayals, Brad is caught between patience and passion.
He's ready to fight for her. Even if she doesn't think she deserves it.