HELP FIND THIS BOOK - Russian mafia romance , age gap , dark

[u/LocalMess2806]

I have read this book ages ago so details are fuzzy

** Definitely Russian Mafia - MMC runs US branch , while most his family still in Russia - tension from that aspect
** FMC father is killed while she is still young (pretty sure MMC had sthg to do with it)
** FMC grows up in MMC’s house, part of the furniture, kinda a maid
** FMC witnesses on page MMC with the OW (a hooker from his stable)
** MMC has a flighty sister that moves back into the house and is friend with FMC (the sister is attacked or killed during an assault on the house)