Most large studies of divorced couples point to lack of commitment as the number one reason for divorce, with infidelity and ongoing conflict typically following close behind. In these studies, around three‑quarters of participants said that one or both partners simply stopped truly investing in the relationship over time.

Quick Scoop

What “lack of commitment” really means

When people report lack of commitment, they usually describe patterns like:

  • One or both partners stop trying to resolve problems and just “check out” emotionally.
  • Avoiding hard conversations, ignoring issues, or constantly threatening to leave instead of working things through.
  • Letting the relationship run on autopilot while work, stress, or other priorities always come first.

Over time, this can feel like the foundation of the marriage has crumbled, even if there was no single dramatic event.

How it connects to other top reasons

Researchers and divorce professionals often list a cluster of leading causes that intertwine:

  • Infidelity or extramarital affairs, which often occur after emotional disconnection has been building for a while.
  • Too much conflict and arguing, where couples never learn to fight in a constructive way, so resentment piles up.
  • Money and financial stress, which magnify existing cracks in communication and trust rather than creating them from scratch.

In many divorces, people say there were multiple contributors, but when asked for the single biggest cause, lack of commitment comes out on top.

What people say in forums

In online discussions where people talk informally about “what is the number one reason for divorce,” a few themes show up again and again:

  • “Forgetting you’re on the same team” – partners start treating each other like opponents instead of allies.
  • Dishonesty and lying (even “small” lies) slowly destroying trust until one person feels they can’t believe anything anymore.
  • Emotional neglect: one person feeling unseen, unheard, or taken for granted for years.

These personal stories echo what the research shows: most marriages don’t end because of one bad day, but because of repeated choices not to show up for the relationship.

A quick note if this feels personal

If you’re asking this because of your own relationship:

  • It is common to feel scared when reading about divorce statistics.
  • Many couples can improve things by tackling commitment, communication, and honesty early with counseling or open, structured conversations.
  • If there is abuse, coercion, or serious emotional harm, it is important to seek professional and legal support in your area.