My Husband’s Mistress Got the Baby, I Got the Throne

From the back cover

Bianca Valentini has loved Marco Ferrante for ten years, hiding her identity as the Don's only daughter to stand beside him while quietly opening every door the Valentini name could offer. When she learns that Marco donated sperm to his female "brother" Serena Marchetti and that both families are celebrating the pregnancy at the Ferrantes' table, she hears Marco and his mother Patrizia dismiss her as someone who would never dare object. She calls her father and asks him to cancel Marco's promotion, then walks in to end the engagement.

Marco and Serena meet her with the ultrasound photo in hand, insisting the baby was a favor and that Bianca should not make a scene. Enzo Ferrante orders her out, and Marco lets her go, certain she will return as she always has. But Bianca remembers the ten years she spent covering his expenses, the night he chose to make Serena ginger tea while she fought for her life alone in a parking garage, and the Maldives trip he took with Serena instead.

This time, the ring is already on the floor.