Wicked Vows by Glenna Maynard

Nico Moretti is as cruel and powerful as he is devilishly handsome.
Everyone knows he murdered his first wife for her inheritance.
He’s also the man my sister is supposed to marry.
Until she betrays him by running off with one of our father’s men.
Leaving me to take her place by Nico’s side at the head of the Moretti Empire.
I’m too young for him, but I have no choice.
My father demands it, and the life of my traitorous sister depends on these wicked vows.
I do.
These two words cement my fate.
I know my duty is to provide my new husband with a child.
What I don’t expect is to enjoy it so much or to fall for him while being haunted by the ghost of his previous wife.

Wicked Vows is a standalone age gap, gothic, mafia romance.