unhealthy trends and vile practices

[mery smith]

Hello, every native speaker,
I don't know how to understand those words in red in following sentence, could you explain its meaning for me?
The unhealthy trends and vile practices such as extramarital affairs, keeping mistresses, and maintaining a lover become fashionable throughout the entire society. Countless families have been destroyed and broken up for this reason. (from a friend)
Thank you in advance.

 

[Florentia52]

It might be best for you to ask your friend why he or she decided to refer to extramarital affairs in this way.