The Billionaire's Secret Shoes - Clean Billionaire Romance, #2

Seven years ago, he broke her heart. Now he's back. Jackson Lebak is happy as a small-time college football coach. Until his eccentric grandmother offers a billion-dollar shoe company as an inheritance. The catch? He has to get married before she dies. He doesn't know a single woman he could even imagine such a future with. But he used to know one. Ruth Koopman is working toward her Ph. D. and drowning in debt.
She's not thrilled when she runs into her old college flame at the coffee shop. He'd broken her heart into so many pieces, she is still picking them up seven years later. She had been so in love with him. She had been so certain she would marry him one day. Then Jackson Lebak knocks on her door and proposes. When she asks him why the sudden rush to the altar, he tells her it's a secret.