Fake Girlfriend/Boyfriend for the Holidays

The protagonist recruits a paid or willing stand-in to pose as their romantic partner for family gatherings, office parties, or seasonal events, with the ruse inevitably collapsing into real feelings.

Readers love the delicious tension of a lie that must be maintained in front of nosy relatives and old flames, plus the slow burn of two people pretending to be in love until they can't pretend anymore.