Health, you would be surprised to know that not all parents impress upon boys, or maybe not all boys choose to learn, the necessity of deodorant, showering every day and/or when married showering at night before bed, brushing their teeth twice a day and using mouthwash, changing their shirt every day, etc, etc, etc.
Not all men know these things or are considerate enough to put their dirty clothes in the hamper, their dirty dishes in the sink, take out the garbage without being asked, etc, etc, etc.
All of which puts a huge strain on a marriage as you can imagine if the shoe were on the other foot so to speak.