watched it years ago so my description might be a little off
its about a wife who’s having an affair with an artist/painter (i guess,idk)
and then the wife and the painter murdered the husband by drowning him
her mother in law was so devastated and turned mute
and at the end of the movie they committed suicide
by drinking poison (i guess,idk)

if im not mistaken, it was released maybe somewhere between 2010-2016
and the movie settings probably something like 1800 or maybe 1900 idk
with the long dresses and corsets and everything

sorry for bad english

Edited question