Adultery
noun, な adjective, の adjective
If you do not have any ethics you'll probably do something crappy, like commit adultery. Usually only unethical people would cheat on their spouse, right?
ふりん
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
どうやら妻が不倫をしているようなんです。
It seems that my wife is committing adultery.