Starting Over with You by Toni Aleo

Kenni Colburn has spent the last nineteen years being the perfect wife, the greatest hockey mom, and the glue holding everyone else together—while her husband built a secret second family. But now that her twins are off to college, she’s done being the woman who puts herself last. Kenni is packing up her car and heading home to Thistlebrook to reclaim her maiden name, her happiness, and maybe even her wild streak.

Dean has been in love with Kenni since he was fourteen, but timing has never been on their side, especially since she’s his sister’s best friend and is also the sister of his baby mama.
That might not have been his finest moment…
Dean is not only the best dad imaginable, but the most reliable firefighter in a community that loves him even if he didn’t marry the woman he knocked up.
She wasn’t the one, and he wasn’t settling for anything but the best.

Now, Kenni is back—fierce and finally free—and Dean knows he’s not letting her slip away this time, even if it means burning every excuse to ashes.

Small towns are supposed to be quiet, but in Thistlebrook, exes return, secrets explode, friendships rally, and second chances set the entire romance section of the library on fire, sometimes literally. Kenni is ready to start over, but she never expected to fall into the arms—and the bed—of the man who’s always been there.