The Billionaire’s Instant Family by Holly Rayner

Their family was supposed to be pretend.
Until their hearts made it real.

Theo Hillman built a billion-dollar tech empire, but Boston’s old-money elite still won’t take him seriously. When he learns that family men earn their trust, the workaholic billionaire makes a bold plan: hire the perfect fake family.
Single mom Nina Thompson is struggling to keep a roof over her son’s head when Theo offers her an impossible deal: move into his mansion, pretend to be his partner, and enroll her brilliant five-year-old in one of the city’s most prestigious schools.

It’s supposed to be temporary. Strictly business.
But as pretend family dinners turn into real laughter and Theo finds himself drawn to the woman who’s turning his house into a home, the lines between fake and real begin to blur…

And when one unexpected night changes everything, Theo must decide what matters more—the deal of a lifetime… or the family he never knew he needed.