Romance/rom-com book with a single dad/nanny who go to a holiday family gathering

I admittedly don’t remember much about this book. I read it several years ago as an ebook.

I’m not sure if they were faking a relationship, or if the FMC just accompanied the MMC on his family trip as an employee. I’m pretty sure she was his nanny.

They go to the MMC’s family’s place for a big holiday (I think it was Christmas bc I vaguely remember a scene with making/decorating cookies with the mother-in-law).

At some point, I think the MMC’s family asks about the FMC’s family and she starts crying or something bc her parents are dead (or there’s some other trauma)

Ik this isn’t much, I’m sorry. If I remember anything else, I’ll update!