How do serial killer's wife not know?

It is said that most serial killers are your average person and that there really is know way to describe what a serial killer looks like. Well in this case that statement is very true. Williams who worked as head of an air force base was happily married and was claimed to be a kind and thoughtful husband. People are asking how is it possible that William's wife not know about his fetish break in's? Phycologists say why would a wife know. Serial killers tend to lead a double life keeping it a secret from their love ones. Even if there is suspicous behavoir it is to much to suspect that the person your living with is a killer. For example John Wayne Gacey would invite boys to his home and proceed to murder them and burry the boys in the basement. Gacey would do this every weekend because his wife would leave to visit family and friends. She never discovered his secret hobbie and carried on clueless and naive. Gary Ridgeway killed four woman while married to Judith Mawson and she had no clue. Ridgeway was said to be the perfect husband treating Judith like he was a coompletely different person. Wifes are way to in love to suspect that their spouse could be doing something so disturbing.