Restart & New Revenge by Allison Bettes

They married fast and fell apart faster. Now her ex is back and so is the danger.

Anna “Ace” O’Hara thought her whirlwind Vegas marriage to Archer Papadopoulos was nothing more than a scorching mistake—one week, one ring, and one hell of a heartbreak. They walked away without looking back. At least, she thought they had.
But when a mafia threat resurfaces—one that traces back to Archer’s old life as a cop—Ace becomes a target. And Archer? He shows up like he never left, sworn to protect her whether she likes it or not.
Now the grumpy security boss and the woman he never stopped watching from afar are stuck side by side, and old sparks turning into full-blown fire. But protecting her means confronting everything they left unsaid, the fallout that followed, and the very real feelings that never died.

Because the danger is closing in fast. And this time, walking away might not be an option.