You said a culture accepts it?

it is not "a" culture... but then again culture has a really broad definition (maybe I misused the word) let us just go with:

"Culture is an umbrella term which encompasses the social behavior and norms found in human societies..." from excerpt wikipedia

You said it yourself in your story... people knew but turned a blind eye, why? If she tells anyone, it will be probably her fault because she isn't a "good" wife, or it is just an accident, and so on and so forth.

this is quite the norm in all countries...

but this and everything else is just my opinion... there are lots of groups whom are more knowledgeable about this. You should ask them for help they have a therapist for your friend to help her cope with the pain and people there whom suffered as well and is well on recovery.

I just remembered a girl whom keeps talking about me about women's rights. 🤣