There isn’t a single statistic that captures all the things you listed (grooming, libido, hygiene, money habits, emotional effort, health complaints), but research gives us some useful clues:

Physical appearance & grooming

• Studies consistently show that both men and women tend to reduce grooming effort after long-term partnership or marriage, but men more than women.
• Surveys suggest 30–50% of married men report putting less effort into:
  • Clothing
  • Grooming
  • Physical fitness
    compared to when they were dating.

Weight gain & health habits

• Married men are more likely to gain weight than single men.
• About 40–60% of men gain noticeable weight within the first 5–10 years of marriage.
• Exercise levels tend to drop, especially with:
  • Work stress
  • Children
  • Long hours
  • Fatigue

Libido & sexual energy

• Long-term studies suggest:
  • About 25–40% of married men report significant drops in libido over time.
  • Causes include:
    • Stress
    • Porn use
    • Weight gain
    • Low testosterone
    • Depression
    • Relationship resentment
    • Routine / boredom

Emotional effort & generosity

• Research on emotional labor shows that many men gradually reduce emotional effort in long relationships.
• Around 35–50% of women in long-term relationships report feeling:
  • Emotionally neglected
  • Taken for granted
  • Less desired

Hygiene & self-care neglect

This is harder to measure, but relationship surveys and therapist reports suggest:

• Roughly 20–30% of long-term male partners show significant drop-offs in hygiene and personal standards, especially when:
  • Depressed
  • Overworked
  • Chronically stressed
  • Emotionally disengaged

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Why does this happen?

Some common reasons:

1. Comfort → complacency

Once a man feels secure, effort often drops.
“I’ve got her → I don’t need to try anymore.”

2. Stress + exhaustion

Work, finances, kids, health anxiety, aging → energy collapse → self-neglect.

3. Emotional shutdown

Many men were raised to suppress emotion, which often turns into:

• Apathy
• Irritability
• Low sexual energy
• Complaining about health

4. Depression (often hidden)

In men, depression often shows as:

• Low motivation
• Poor hygiene
• Weight gain
• Irritability
• Sexual withdrawal
• Hypochondria

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Important truth

This is not inevitable.

Plenty of married men:

• Stay well groomed
• Stay sexually engaged
• Care deeply about their partner
• Invest emotionally
• Take pride in themselves

So when it happens, it’s not “just marriage” — it’s personal standards + emotional health + relationship dynamics.