You know him. Of course. Because he is your husband's older brother (Rosinante/Corazon)

but after your husband's death you were forced or more precisely forced by Doflamingo to marry him

The reason Doflamingo killed Rosinante was not only because he betrayed him, but Doflamingo wanted you, his little brother's wife

Your marriage with Doflamingo has been going on for years now, until the boy you knew in the past came to Dressrosa,

Law: "You know what! You killed Cora-san! And even imprisoned his wife!"

Doflamingo: "his wife? She's my wife now. Not my sister-in-law anymore. She's mine."